Frequently Asked Questions
What are the suggested R-values for the various components of a home?
The best, most current information suggests the range of R-values in the table below.
|Ceilings||R-30 to R-40|
|Walls||R-13 to R-24|
|Floors over unheated spaces||R-20 to R-24|
|Basement Walls||R-9 to R-15|
|Crawl-space walls||R-10 to R-16|
The value chosen within the range you should pick depends on where the house is located in the state. Lower R-values are more appropriate in southeastern Kansas, while homeowners in northwest Kansas should consider higher R-values. Those living in the central part of the state should aim at a value somewhere in the middle of the range. An R-value is the measure of a substance's resistance to temperature change. Select a building system that will provide R-values within or above these ranges, and see that materials are installed so as to create a well-sealed structure.
Which areas in a home would benefit the most from insulation?
Most heat lost in uninsulated homes is through the roof.
Because the attic is usually accessible, it is an area that is easy to insulate. If the attic has not been insulated, first install a vapor barrier directly above the ceiling, then place insulation up to an R-38.
Some types of insulation have a vapor barrier attached directly to them. This insulation should be installed so that the vapor barrier is toward the warm side of the house in winter.
If there is already insulation in the attic, don't install another vapor barrier over the old insulation. It is acceptable to mix types of insulation, such as adding cellulose over fiberglass batts.
Of equal priority to insulating an attic is to seal and insulate any exposed ductwork that runs through unheated areas, such as crawl spaces and attics. These ducts should be insulated with a minimum of an R-11.
If the ducts are used during the summer for central air conditioning, the insulation should have a good vapor barrier on the outside of the insulation. This will prevent condensation from forming on the cold duct due to the humid summer air.
The next priority is to insulate unheated crawl spaces either directly beneath the floor or on the foundation walls. If insulating below the floor, install the vapor barrier on the warm side in winter, or facing up.
Be sure that any plumbing in the crawl space is on the warm side of the insulation to keep the pipes from freezing.
Insulating crawl-space walls is appropriate only in unventilated crawl spaces. Insulation on these walls should run from the band joist down the foundation wall and extend at least 2 feet across the floor of the crawl space. The band joist is the area between the foundation wall and the floor of the room above the crawl space.
The dirt floor of the crawl space should be covered with a polyethylene film.
Insulating basement walls is the next priority and is just as important as crawl-space insulation. It is possible to add furring to the wall, insulate between the furring, and add a finished surface, such as wood paneling. Or, attach rigid foam directly to the basement wall and cover it with a noncombustible material, such as gypsum board.
Although not generally considered a do-it-yourself project, installing wall insulation can be very cost effective. This requires drilling through the siding or removing some of the siding and drilling through the sheathing under the siding. Knowledge of building construction is helpful to make sure that all wall cavities are filled with insulation. Wall insulation installed at the proper density and with no voids will not only significantly reduce conduction heat loss through the walls, but can reduce air leakage as much as 30 percent.
How does one achieve an R-38 in the attic near the edge of the roof?
The problem arises at the joint where the roof, wall, and ceiling come together.
Full-depth insulation may cut off continuous ventilation.
It is necessary to maintain one inch to one and one-half inch of air space over the insulation from the soffit area into the attic. Full-depth insulation to the outside face of the wall is desirable.
If this insulation is not firmly fixed or protected, it may be moved by winds and air pressure moving through the soffit vents. This may lead to moisture problems on the interior sheetrock finish.
The best solution to both problems is to use raised-heel roof trusses with sufficient depth over the wall for the necessary insulation. Regardless of the roof construction, the edge of the insulation over the wall should be protected by baffles, which are flush with the exterior face. The baffles should turn up and follow along the truss, maintaining a vent space under the sheathing.
This should prevent wind-driven movement of insulation and reduce the possibility of moisture problems at the ceiling perimeter.
Which is better for insulating attics, fiberglass or cellulose?
Both products are excellent insulating materials. Either can be used for insulating an attic, but, generally, cellulose is easier to install and is usually less expensive. Cellulose also has a slightly higher R-value per inch thickness and is more effective in reducing air leakage.
Some studies have shown that cellulose insulation retains its insulating value at lower temperatures when compared to fiberglass. Based on these points, cellulose is the preferred insulation for most attic arrangements.
However, be sure to seal all holes in the attic floor before beginning to insulate, regardless of which material is used.
Should I use a radiant barrier in the attic instead of conventional insulation?
No. In Kansas's winter climate, conventional types of insulation are necessary to cut heat loss from the interior of the house through the ceiling. Installing insulation properly and careful attention to air sealing will reduce air leakage through the ceiling.
A radiant barrier provides the greatest savings in the summer by reducing radiant heat transfer from a hot roof to the attic floor. However, they generally have not proven to be cost effective in Kansas's climate.
How can I insulate my floored attic?
One of the simplest methods is to drill holes in the flooring and then blow cellulose, mineral wool, or fiberglass into the opening. This method is like blowing insulation into walls. It is possible to use holes as small as 1 inch in diameter, but larger holes provide better coverage. For each joist cavity, drill at least three holes. Holes should be located at both ends of a joist cavity and in the middle.
Another approach involves opening the center section of the floor and then using an insulation blowing tube. This tube is inserted through the floor opening between the ceiling joists (attic floor joists). The tube should be long enough to reach the far end of the joist cavity.
Next, blow insulation through the tube to fill the far end of the cavity. When insulation stops flowing, withdraw the tube about 18 inches. The flow will resume as the tube is withdrawn. Continue the process until the entire cavity is filled. The blowing tube is typically a 2-inch diameter, clear vinyl tube that is attached to the insulation blower's regular tube.
How do I seal my attic access panel?
Many people place a single piece of sheetrock or a quarter-inch-thick plywood piece over the panel. But this is not an effective way to reduce heat loss or form a tight seal with the frame.
A better solution is to add insulation to the top (attic side) of the panel. The insulation can be either fiberglass batt or rigid foam, and it should be thick enough to equal the R-value of the attic insulation. If there is loose-fill insulation in the attic, some of it may spill into the home when the access panel is opened. The easiest way to avoid this is to build up a frame around the opening.
The frame can be made with plywood, lumber, or even heavy cardboard. Apply weather-stripping to this frame to reduce air leakage. The drop-in panel should be heavy enough to form a tight seal with an adhesive foam strip.
Finally, caulk the ceiling trim around the opening to further stop leakage.
How should I insulate a slab-on-grade floor?
A concrete slab floor should be insulated first at the edge of the slab where it is exposed to the outdoor air and then down the face to the frost line or below. A foam board type of insulation is most suitable, usually extruded polystyrene with enough thickness to achieve an R-value of at least 12.5.
Insulating beneath the floor depends on a number of factors. If the slab is to be covered with carpet or other insulating materials, insulation is not needed underneath. Definitely insulate under the slab if there are any buried or in-slab heating systems, and do so in consultation with the manufacturer's and installer's recommendations. If the slab area is small or exposed on two or more sides, insulating the sides and underneath will tend to keep the slab warmer.
If the slab is to be used for direct-gain passive solar storage, insulation will reduce the heat loss to the earth below and keep the floor more comfortable. Insulate wherever the sun will strike the floor and where desired for comfort.
In larger slabs, a 4-foot-wide band near the edge may be sufficient.
If the slab rests on damp, wet soil, it will tend to lose heat more rapidly and insulation will help retard this loss. In general, 1-inch thickness of polystyrene should be adequate for most installations.
How can I seal and insulate the opening for a whole-house fan?
The metal louvers under a whole-house fan offer little protection against heat and air loss to the attic in winter. Consider attaching an insulated panel directly below the louvers. To make this an easy, seasonal task, build a frame using 1 by 2-inch lumber to hold the insulated panel.
Cut the panel from five-eights-inch rigid insulation board, and mount it in the frame with fabric or other decorative material. Four wing nuts mounted in the frame will hold the panel in place. Taping a sheet of plastic under the louvers will help stop air leakage but will provide little insulation.
Windows and Doors
What are some common window types and their characteristics?
U-value is a measure of a material's ability to transfer heat. A window with a low U-value is better than a window with a high U-value.
Most single-pane windows in a home probably have a U-value of about one. Adding another pane of glass (referred to as double-glazing) will lower the U-value to about 0.5. The technique of double-glazing creates an air space between the panes of glass. This air space reduces conductive heat loss through the window.
By adding yet another pane of glass (triple glazing), the U-value decreases to about 0.31.
The U-value of window units is the heat flow at the center of the glass, and this is generally lower than overall U-value of the window. The overall U-value of a window includes the glass or glazing, the frame and the sash.
One common method of reducing heat gain or loss through windows is by coating the glass with an invisible, heat-reflective material. This type of glass is called low-emissivity, or low-e, glass.
A double-pane window with a low-e coating has a U-value of about 0.36, which translates to 35 percent less heat gain or loss than conventional double-pane windows. Triple-pane, low-e window units are also available and have a U-value of approximately 0.25.
Another type of window that's available is one that is gas filled, usually with Argon or Krypton. These gases are more viscous, slow moving and less conductive, reducing convective currents in the air space, lowering the heat transfer between inside and outside.
How can I choose a replacement window that will give good performance at a reasonable price?
The lowest U-value available for what a budget allows are recommended.
U-values are a measure of how much heat is lost through the window and frame.
Window frames are manufactured from different materials (wood, plastic, metal) have one, two or three glass layers, use special and light-reflecting films, and use air or special gas fillings between glass panes. The possible combinations number into the hundreds.
Fortunately for consumers, the National Fenestration Rating Council now publishes its Certified Products Directory that lists U-values for windows.
The catalog is available online at http://www.nfrc.org/.
The Certified Products Directory allows comparisons of specific models from several manufacturers.
Detailed rating information is also attached to new windows on a temporary label. This label is designed to provide consumers, builders and code officials with energy performance information in a comparable, easy-to-read format. The temporary label is accompanied by a permanent label or marking somewhere on the product, usually in an area that is unseen when the window is closed.
Pricing information is available from suppliers.
What are low-emissivity windows, and what are their advantages?
Low-emissivity windows have a special coating on the glass that reduces radiant heat transfer, thereby increasing the window's insulating value.
Emissivity refers to a surface's ability to radiate energy and is expressed as a value between zero and one. The emissivity of clear glass is about 0.85. A low-emissivity coating can reduce that to about 0.15, reducing the U-value of a double-glazed window from 0.5 to almost 0.3.
This has the same U-value as triple glazing, but without the increase in weight or size and at much less expense. Low-emissivity coatings also reduce solar transmission. This is an advantage in summer, but a disadvantage for south-facing windows in winter.
The year-round benefits of low-emissivity windows outweigh any loss of winter solar heat gain, and are appropriate for any window orientation.
What is the advantage, and expected life, of purchasing gas-filled double-pane windows?
The advantage of having argon gas between the panes of glass is that argon transfers less heat than air does. Argon has a lower U-value because it is denser than air. This reduces heat transfer within the air space.
Argon-filled glass windows have U-values ranging from 0.40 to 0.31, while air-filled windows have U-values of about 0.5. For homes with a significant amount of window area, about 25 to 40 percent of the house's square footage, this U-value difference can cut energy costs significantly.
Over time, argon gas may leak out of the space between the panes of glass. The amount lost depends on how well the window was manufactured and the quality of materials used. Argon leaks are usually caused by failure of the seals between the glass and the edge spacer. Also, some gas is lost because it diffuses through the seals. Even if the argon gas does leak, the window's thermal performance isn't affected much as long as there is no noticeable failure of the seal.
Tests have shown that if an argon-filled window leaks five percent of its gas each year, it will lose only 12 percent of its R-value after 20 years.
Does condensate on a double-pane window mean the seal has failed?
The location of the moisture indicates whether or not the seal has failed.
On a sealed double-pane window, the space between the panes is filled with a dry gas and may contain a desiccant, a material that absorbs moisture.
If the moisture is between the two glass layers, yes, the seal has failed. Contact the window supplier for a remedy.
If the moisture can be wiped from the room-side surface of the inner pane, the moisture is condensing from the room. On a double-pane window, this simply indicates high humidity - not a failed seal.
To avoid this condensation on windows, remove moisture from inside the home. This can be accomplished by using exhaust fans in the kitchen and bathroom.
What is movable insulation?
Movable insulation is a versatile window covering that allows beneficial heat gain during winter, and minimizes unwanted heat gain in summer.
Insulating windows can make a significant difference in energy bills, since windows are to blame for much of summer heat gain and winter heat loss. This is due to the low R-value of the glass pane.
R-value measures resistance to heat gain or loss.
A typical insulated wall has an R-value anywhere from 12 to 19, while a double-pane window has an R-value of about 2. By using movable insulation within the window frame, the R-value nearly doubles. This will help reduce a home's overall heating and cooling load.
Movable insulation is divided into two types: interior and exterior. Examples of interior movable insulation are thermal curtains, shades, shutters, and window quilts.
Shades and shutters keep out (or retain) the most heat, but also cost more than curtains and window quilts. Shades are most effective if they are properly sealed along the edges of the window. Interior shutters are usually made of polystyrene or a foam sheathing encased in wood or metal, and can triple the R-value of a window.
The most common type of exterior movable insulation are shutters. Most people who use movable insulation place it inside their home. The advantages of interior insulation are protection from the weather and simplicity of operation.
Exterior movable insulation has advantages as well.
Exterior shutters provide additional security to a home and can reflect more sunlight into a home during winter months. They also do a better job of reducing solar load in the summer. However, shutters generally cost more than interior insulation, and are subject to constant weathering.
What is the best way to shade a window to keep out summer sun?
An exterior shading device is best because it stops the sun's heat outside the home.
Perhaps the ideal choice is natural vegetation. Properly positioned trees and shrubs can provide the most effective shading to match cooling season demand and will enhance the local climate of the building.
Adjustable horizontal or vertical louvers, installed on the outside of the window, provide the most complete shading but cost more than most other sun control devices. Awnings, generally the most widely used exterior sun control device, provide good shade while permitting full ventilation. Awnings should be opaque and vented at the top to prevent heat build up underneath.
Reflective solar screens stop between 30 and 70 percent of the light and heat outside a window without stopping ventilation. Solar screens have the advantage of being removable in the winter to allow the sun's heat into the home.
Window films and aluminum foil taped to windows are inexpensive interior treatments but less effective than exterior devices. White or light-colored roller shades and drapes help reduce incoming sunlight and heat.
Dark shades or drapes and venetian blinds are the least effective sun control devices.
What types of doors are the most energy efficient?
The most energy efficient doors are those that seal tightly when closed.
This requires a quality weather-stripping system and a door that resists warping. The insulating value of the door is also important.
Metal and fiber glass doors are available with urethane foam cores that provide R-values up to 4.4, compared with an R-2.1 for a solid-wood door. A metal door has the added advantage of using magnetic gasket weatherstripping that works much like the seal on a refrigerator door.
It's important to keep door-related energy costs in perspective.
In Kansas, a typical solid-wood door with average-fitting weather-stripping contributes only about $9 a year to heating costs.
What plants are best for shading west windows?
Plants are useful because they can provide shade during the time of day and year when overhangs are losing their effectiveness.
Some that have been suggested include Virginia creeper, a number of ivies, and euonymus. The local county extension horticulturist or a local nursery will know exactly which plants do best in different areas.
Fruit trees also can be trained to grow along a trellis. Some of the most useful are trellises made of wood framing and weather?resistant cord or wire. The wood should be cedar, redwood or pine that has been thoroughly sealed and painted. The trellis can be fan?shaped or rectangular.
Avoid using black wire for the cross supports because this can acquire so much heat from the sun that it can burn young vines.
Also, keep the trellis more than 1 foot from the wall being shaded, or heat reflected from the house may injure the plants.
Which is the better method for insulating basement walls: exterior or interior insulation?
Both methods can be used effectively to reduce heat loss, and each has advantages and disadvantages.
The preferred method, from a thermal standpoint, is exterior rigid foam board insulation. It allows the concrete to interact thermally with the interior and helps reduce temperature fluctuations.
Exterior insulation for a basement wall must be protected from the sun and physical damage.
A major disadvantage to exterior insulation is that it provides a hidden entry path for termites. For this reason, exterior insulation should only be used in areas where the threat of termites is low.
Interior basement wall insulation is less costly, easier to install and provides a finished living space with room in the walls for utilities. Also, most builders are familiar with the techniques.
How deep should foundation insulation extend below grade?
Insulation should extend all the way to the footing. A heated basement will always lose heat through its walls, no matter how deep they are.
Although heat loss to the soil near the bottom of the wall is not great, heat is conducted up the wall to colder soil near the surface. Insulating the entire wall reduces this bypass heat loss.
Also, keep in mind that the cost of the additional insulation is relatively small compared to the cost of framing and finishing the wall.
What is the R-value of soil?
The resistance of soil to heat flow (R-value) varies a great deal, depending on the type of soil and the moisture content. In general, soil is not a good insulator.
For a fine-grained soil with 20 percent moisture content, the R-value is about 1 per foot, roughly the same as concrete.
Because of this low R-value, it is important to insulate foundations, including slabs-on-grade, crawl space walls and full basements. Insulating the first few feet below grade is the most critical area, but we recommend full-depth insulation.
Where are the most critical air leaks in a home?
These are likely to be found in the attic, as holes around plumbing and electrical lines, and other gaps in framing. If this is an existing home, move the insulation out of the way to find many of these. Using a foam sealant, regular caulk and small pieces of foam board, seal all the penetrations possible. Look for other openings in both exterior and interior walls, including plumbing openings behind bath and kitchen cabinets.
Residents should be sure to replace the insulation and avoid leaving gaps between fiberglass batts. In homes with a basement, owners should look for, and seal, the same kind of holes in the ceiling and floor framing that open into the interior cavities of the house.
After sealing is done, consider adding insulation to the attic. An attic should be insulated to an R-38, or about 12 inches fiberglass or cellulose. When adding attic insulation, cellulose can be blown directly on top of either fiberglass or cellulose. Many lumberyards will loan the equipment when purchasing the insulation from them.
For additional help, a do-it-yourself energy audit is available online at the Energy Extension Web site at http://www.oznet.ksu.edu/dp_nrgy/ees/. Some may also choose to hire a certified Kansas home energy rater. Call Energy Extension at 1-800-KSU-8898 for a list of professionals.
What is an air barrier, or house wrap?
These products are primarily designed for use in new construction as a method of reducing air infiltration. They are rolled sheet goods usually installed with staples or tape over the exterior sheathing.
Some brand names are Tyvek, Rufco-wrap, Barricade and Airtight-wrap. Their intent is to minimize the passage of air, while still allowing water vapor through the exterior skin of the building.
Three basic types currently are available. Tyvek is a spun-bonded polyethylene. This is a mat of polyethylene fibers spun-bonded in a patented process. The second type is perforated polyethylene film. The third type is spun-bonded polypropylene, a different type of plastic.
Each of these can be effective air barriers if installed according to its manufacturer's recommendations.
How effective is covering windows with plastic at sealing a window?
Properly applied, a plastic covering can make a window almost airtight. This is one of the most effective ways to seal a leaky window.
A storm window is designed more for convenience and appearance than air tightness. Even the highest quality storm windows allow air to leak around the edges of the sashes. Storm windows typically reduce air leakage through primary windows by about half.
Window plastic can be installed on the inside window surface or on the outside. It will be more difficult to maintain window plastic applied to the outside. Cold temperatures make the plastic brittle, and winds whip the plastic in and out, reducing the seal's effectiveness and sometimes even tearing the plastic.
Newer plastics are very clear when stretched tight, so do not need to worry about window coverings reducing a home's appearance. Special shrink film plastic can be heated with a blow dryer to shrink the window film and eliminate all wrinkles, making the plastic almost invisible.
For maximum leak reduction, it is important to adhere the plastic to the frame surrounding the window rather than to the window sash.
Can I close some of my attic vents during the winter?
Yes. However, assuming that an attic is properly insulated, there isn't much advantage in closing the vents in winter.
Because insulation is typically in the floor of the attic, the attic temperature will be close to that of the outdoor surroundings. Closing some vents won't significantly change this temperature.
An attic requires a certain amount of ventilation during the winter for moisture removal. This ventilation area is about half that required during the summer.
An attic will require more ventilation if significant moisture sources exist, such as kitchen or bathroom vents.
How important is crawl space venting?
Crawl space ventilation is required by code in many areas. However, a growing body of research indicates that it often is not effective in reducing moisture levels in crawl spaces.
The two most important methods to deter moisture accumulation in crawl spaces are adequate drainage away from the foundation, and a moisture barrier over the soil in the crawl space.
Drainage can be created away from the foundation walls with a minimum 5 percent slope for a distance of 15 feet from the foundation. This is the ideal. Dense ground covers like healthy turf grass also help surface run-off to drain away from the foundation.
However, even soil that feels dry inside a crawl space can be a significant source of moisture. Keep this moisture in the soil and out of the crawl space by covering the ground with a six-mil plastic vapor barrier. Overlap seams in the plastic a minimum of six inches and extend the plastic up the foundation walls six to 12 inches. Use soil, sand or rocks to weight the plastic down around the perimeter and over seams.
Is there a simple rule for sizing a kitchen or bathroom exhaust fan?
Yes, but the rule for the kitchen is different than for the bathroom.
Exhaust fans are rated by their air-moving capacity in cubic feet per minute, or CFM. The rules of thumb relate the required CFM to the volume of the space to be ventilated.
To size an exhaust fan for a kitchen, multiply the volume in a kitchen (length by width by ceiling height) by 0.20. A 12 by 12 foot kitchen with an 8-foot ceiling would require an exhaust fan rated at 230 CFM.
Kitchen exhaust fans should move at least 200 CFM as a practical minimum. A bathroom exhaust fan should move 0.13 CFM per cubic foot of space, with a minimum of 50 CFM.
Exhaust fans must be vented to the outside, not into an attic or crawl space. The venting duct should be as short as possible and have few right-angle bends. Using a flexible ducting material, pull it tight between the exhaust fan and the vent terminal while avoiding sharp bends. Then cut off any excess material. Improper ducting can reduce exhaust fan air flow by 50 percent or more.
A backdraft damper is recommended to prevent cold air from entering through the exhaust fan when it is shut off.
How do I select a quiet exhaust fan?
A sone is a subjective unit of loudness. Sone ratings for exhaust fans typically range from a low of one to a high of seven. The smaller the number, the quieter the fan.
However, the quietest fans move the least amount of air.
Don't sacrifice adequate air-moving capacity for quietness. Choose a fan that can do the job.
Once the capacity of fan needed has been determined, compare sone ratings on fans of equal capacity and choose the fan.
Can I vent my bathroom and kitchen exhausts into the attic?
Although the practice is quite common, direct venting to the outside is the recommended method. A well-ventilated attic can easily handle the moisture diffused through the ceiling, but it may be overwhelmed by the moisture from a steamy bathroom or busy kitchen.
The greatest danger is that moisture will condense and freeze on the cold underside of the roof deck near the exhaust outlet. If frost accumulates, it can result in enough water to drip down onto the insulation and ceiling.
Through-the-roof vent kits are available, and they are relatively easy to install in composition shingle roofs. Carefully installed, they are not likely to leak.
Will a wall with a five-eighths-inch thick, foil-faced sheathing on the outside and a 6-mil plastic vapor barrier on the inside have moisture problems?
There is the potential for a moisture problem, but the likelihood of this depends on the quality of the installation.
If warm, moisture-laden air from inside a home gets into the wall, and the inside face of the foil is cool enough, condensation could result. If the inside vapor barrier is carefully installed and sealed to prevent air leaks, this potential is significantly reduced.
The other factor affecting the potential for moisture problems is the temperature of the inner foil face. Because the sheathing has a high R-value, there's less chance the foil face will be cold enough to cause condensation.
What is a vapor barrier?
A vapor barrier is an impermeable material, typically plastic or asphalt paper, attached to insulation.
The purpose of a vapor barrier is to prevent moisture from passing through the insulation and condensing on the cold outer surfaces. A vapor barrier has two main functions: keeping moisture inside a home, and preventing it from condensing in the insulation.
In new construction, a sheet of polyethylene film is applied to the studs before installing the drywall. Always apply the vapor barrier on the warm side of the wall, ceiling or floor.
If insulation is to be blown into an attic, lay down the sheet of polyethylene film first, or attach it before the sheetrock is added.
Everyday household tasks such as washing, cooking and bathing release moisture inside the home. A vapor barrier slows the movement of this moisture from the home's interior to the outside, raising indoor humidity levels and preventing condensation in the wall or attic.
Will installing a vapor barrier make the walls sweat?
No, but it's easy to confuse the installation of vapor barriers with moisture problems because vapor barriers do effect indoor relative humidity.
The purpose of a continuous vapor barrier is to prevent moisture from entering wall cavities and attics, where it can condense on cold surfaces and cause structural damage.
The vapor barrier also reduces air leakage. Moisture produced by household activities accumulates quicker because of the reduced airflow, resulting in a higher relative humidity. If the humidity gets high enough, windows and other cold surfaces begin to sweat, or condense moisture.
Condensation problems can be more serious during a new home's first winter. This is due to extra moisture stored in drywall from joint compound and paint. Use of exhaust fans during periods of peak moisture production, such as while showering, bathing, cooking and wet cleaning can prevent or control moisture problems. Construction-related moisture problems will diminish with time as finish coatings cure. However, additional ventilation may be necessary during a new home's first winter.
Lighting and Appliances
Are $10 compact fluorescent lamps cost-effective?
Yes, cost-conscious consumers know these lamps can save energy and money, and they last a long time.
A standard, 60-watt lamp lasts only about 1000 hours. A 15-watt compact fluorescent lamp with the same light output will last more than 10,000 hours and use much less electricity. To get 10,000 hours of use from a standard incandescent lamp, it would take 10 light bulbs at about 50 cents each that would consume more than $40 in electricity, a total cost of more than $45. By using a compact fluorescent, the lamp cost might be $10, but it would use only about $10 worth of energy for a total cost of $20.
These lamps are best used in fixtures that get used a lot or where the lamps are difficult to change.
What is the best exterior lighting source?
The best type of lighting depends on the desired use.
For example, low-pressure sodium lamps have the highest lumen per watt output (amount of light produced per watt of energy consumed) out of all light sources. However, the distinct yellow color of low-pressure sodium lamps limits their use to area lighting, such as parking lots and security lighting.
High-pressure sodium lamps have improved color. They are not as efficient as low-pressure sodium lamps but are still effective light sources and are well suited for general-purpose lighting, parking, or as street lamps.
Metal halide lamps are the preferred light source for outdoor sports activities. The light produced by these lamps has good color and looks more natural than the yellow light of sodium lamps. The output and efficiency of metal halides is lower than either of the sodium lamps but much improved compared to the less expensive mercury vapor lamps.
Are mercury yard lights efficient?
Mercury vapor lamps are more efficient than incandescent lamps, but to substantially improve the efficiency of outdoor lighting, use high-pressure sodium lamps.
Lighting efficiency is a measure of the amount of light from a lamp, in lumens, divided by the power to the lamp, in watts. A 100-watt mercury lamp has an efficiency of 38 lumens per watt. The efficiency of an incandescent lamp is about 16 lumens per watt.
Sodium lamps producing about the same light as a 100-watt mercury vapor lamp have an efficiency of 70 lumens per watt, more than four times more efficient than incandescent lamps, and twice as efficient as mercury vapor.
The smallest sodium lamp is a 35-watt lamp. It will produce more light than a 100-watt incandescent. It takes about five minutes for a sodium lamp to brighten, so they shouldn't be used where they will be turned on and off frequently.
Can a photocell be installed on my outside lamp?
Yes, a photocell can be installed. The switch is about $20. It should be mounted near the lamp but in a location where the light won't shine on the sensor.
Does it cost more to turn a light on and off rather than just leaving it on?
Turning lights off when they are not needed will always save energy. The momentary power surge caused by turning a light on is so small and so brief, it won't even register on a electric meter.
However, frequent switching of fluorescent lamps will shorten their life, eating into the savings of turning them off. Even so, fluorescent lamps need only be off a short period of time for the energy savings to exceed the cost of reduced lamp life. Thus, if planning to be out of a room for more than about 15 minutes, shut fluorescent lamps off.
Practically speaking, incandescent lamps are not affected by frequency of switching. Shut them off whenever they are not needed, no matter how short the time period.
What are the advantages of halogen lamps compared to regular incandescent lamps?
Halogen lamps have a longer life, better color and the light output does not depreciate with lamp age.
Traditional incandescent lamps darken with age. Halogen lamps employ a special gas mixture, higher temperatures, and special glass to improve lamp life and eliminate lamp darkening.
In addition to longer life, halogen lamps offer very clean, bright white light, especially useful for retail display. The lamps are also used in reading lamps or other applications where light quality is important. However, halogen lamps do not have a second glass envelope that limits bulb surface temperature. Therefore they should be used with extreme caution. Bulb surface temperatures of up to 1,100 degrees Fahrenheit are possible.
Some halogen lamps are slightly more energy efficient than regular incandescent lamps. However, if lower operating costs are the motive, consider using compact fluorescent lamps. Several manufacturers have announced plans for an energy-efficient torchiere. Contact EPA Energy Star at (202) 233-9841 for a list.
What should I look for when buying a new water heater?
In general, about 20 percent of the energy consumed by an average home is for water heating. Water heaters have improved significantly in the last 12 years and are much more energy efficient, primarily due to more efficient combustion for gas models and added insulation.
Because the average life expectancy of a water heater is about 13 years, it is important to consider purchasing one that is energy efficient since energy-efficient models mean reduced energy consumption, which results in lower energy costs.
Most water heaters and other home appliances come with a large yellow sticker called the ENERGYGUIDE. This sticker compares average yearly energy operating costs for different models, telling consumers which ones are expected to cost the least during their lifetimes.
Also, most water heaters come with an Energy Factor (EF) value, which is listed on a separate tag beside the ENERGYGUIDE. The EF is a decimal value between 0.4 and 1.0 and is the amount of energy supplied to the heated water, divided by the water heater's total energy consumption. Gas water heaters have EF values between 0.5 and 0.7, while electric ones range from 0.75 to 0.95. Minimum EF values range from 0.51 to 0.56 for gas units, depending upon the size of storage tank, to an average of 0.89 for electric ones. Recommended EF values are 0.61 for gas units and 0.92 for electric water heaters.
All type of water heating units with higher EF values generally cost more initially, but because of the higher EF value, will more than makeup for this higher initial cost in yearly energy savings throughout the lifetime of the water heater.
How do you select the proper size for a water heater?
The size or capacity of water heater needed is based on the maximum amount of hot water consumed during any one-hour period. This is called the peak-hour demand.
To determine the peak usage hour for a family, list all the water consuming activities during that period.
Typical hot water consumption in gallons per usage for various activities is as follows: shower, 20; bath, 20; shaving, 2; hands and face washing, 4; hair shampooing, 4; hand dishwashing, 4; automatic dishwasher, 14; food preparation, 5; automatic clothes washer, 32.
The peak for one family might occur in the morning and consist of three showers (20 gallons each, 60 gallons total), hands and face washing (5 gallons), shaving (2 gallons), and food preparation (5 gallons), for a total of 72 gallons.
A water heater can provide more than its storage capacity during the first hour of operation, because it can also heat the water during this period. This capacity, the total gallons of hot water the heater provides during this first hour, is referred to as the first-hour rating.
In the sample above, a water heater with a first-hour rating of at least 72 gallons would be required.
Residential water heaters are most commonly available in 20, 30, 40, and 50-gallon capacities with first hour-ratings ranging from 22 to 100 gallons. Gas and propane water heaters typically have higher first-hour ratings than electric heaters of the same storage capacity.
How can I reduce my water heating costs?
Several simple things can be done to decrease the amount of energy used to heat water in a home. Water heaters consume about 20 percent of the energy an average home uses, with more than one-third used in showering and 25 percent to wash clothes.
Implementing certain energy-efficient measures, even small ones, can make a noticeable difference in the heating bill.
For example, water heater temperatures should be set to about 120 degrees and definitely no more than 130 degrees. In general, a 10-degree reduction in water temperature has been shown to provide an eight percent water-heating energy savings.
Another important and effective energy-saving measure is to wrap the water storage tank with an R-12 insulation blanket, especially if the water heater is an older model. Consult the manufacturer's equipment guide to make sure an insulation wrap is recommended; it may not be on some newer models. Also, insulate all exposed hot water pipes with either foam or fiberglass wrap.
Installing low-flow showerheads has been shown to save not only money in reduced water usage, but also to save energy as well.
Finally, when the time comes to purchase a new clothes washer, selecting one that is energy efficient will also save on water heating costs.
These energy-saving tips cost very little and have the potential to not only lower the amount of energy used to heat water in a home, but also save money as well.
What can you tell me about tankless water heaters?
Tankless, or demand, water heaters don't have storage tanks, so they heat water as it is used, on a demand basis.
Because there isn't a storage tank, this type of water heater can save from 10 to 20 percent on the cost of heating water.
A family of four uses about 100 gallons of hot water a day. During the course of a year, the cost to heat this amount of water will vary from $90 to $700, depending on the price of energy. If fuel prices are high, the savings gained from a tankless water heater will be significant. Tankless heaters are available in either point-of-use or central styles.
Point-of-use heaters are installed near each area that requires hot water. This minimizes plumbing for new construction. The other type, a central tankless heater, supplies water for the entire house. Tankless water heaters generally cost $200 to $500 more than conventional water heaters. While this may seem like a large premium to pay, the fuel savings may justify the additional cost during the course of just a few years.
What should I do to keep my water heater operating at maximum efficiency?
As with any heating or cooling device, regular maintenance of water heaters goes hand-in-hand with efficiency and safety. Follow these three steps to assure the water heater is giving maximum efficiency for minimum dollars.
1. Every two months, connect a hose to the bottom drain. Open the valve all the way, letting the water flush through. Be careful: this is hot water! This removes sediment, which reduces heating efficiency.
2. Place a bucket under the temperature and pressure (T-P) relief valve discharge, located on the top or side of the heater. Carefully lift the lever -- again, the water surging out will be hot. The T-P valve is a safety valve designed to prevent the tank from exceeding safe temperature and pressure levels. This test assures that sediment is not blocking the T-P valve.
3. If the unit is gas or electricity, annually inspect the heater's burner area, checking for dirt or water. If the area is dirty, shut off the pilot and clean the burner with a shop vacuum. Remember to light the pilot again. If there are signs of leaks, the water heater will probably have to be replaced, soon
If the water heater is more than and the bottom drain and T-P valve have never been checked, they may not seal properly once opened. Replace either valve if they do not seal tight after operation.
Should I use a water heater insulation blanket with my new water heater?
Residential water heaters must all meet minimum efficiency standards. For example, a 40-gallon, gas water heater must have an energy factor (EF) of at least 0.54, while an electric water heater must have an EF of at least 0.89.
While this is a considerable improvement compared to heaters marketed just a few years ago, there are water heaters on the market with EF ratings in the mid-60s or higher for gas and the mid-90s for electric.
If the existing water heater is on the low end of the efficiency rating, then it is still possible to reduce fuel cost effectively by adding an insulation blanket. However, if the water heater is on the high end of the efficiency range, then additional insulation will probably not be of much benefit.
Can you vent a water heater to an old masonry chimney?
The National Fire Code does not specifically prohibit the use of masonry chimneys with modern gas appliances. However, it requires the chimney to be lined with an approved material.
Many old masonry chimneys are not lined. Venting gas appliances into unlined chimneys could cause drafting problems for the appliance, as well as deterioration of the masonry.
It is recommended that gas appliances are vented with a properly sized and designed chimney. Check with local building code officials for their specific requirements.
Will a ceiling fan help save energy?
A ceiling fan saves energy primarily by enhancing comfort in the summer. The amount saved will depend on how much less an air conditioner is used. A fan creates air movement that can help the room feel cooler at higher air temperatures.
Research has shown that moving air can compensate for a four-degree increase in air temperature with no perceived loss of comfort.This means someone can be as comfortable at 82 degrees with a fan moving air, as someone would be at 78 degrees with no air movement.
For each degree increased on the thermostat setting in the summer, expect to save three to four percent on the cooling bill. So, if someone operates a ceiling fan and raises the thermostat setting four degrees, 12 to 16 percent will be saved.
Keep in mind the thermostat must be kept at the higher setting to achieve the expected savings. And, in order to be comfortable, a fan may be needed in each room of the house. Install a ceiling fan in the most frequently occupied room, such as the family room, and use several portable fans to move air between rooms. Any type of fan can enhance comfort in summer, not just a ceiling fan.
In the winter, ceiling fans recirculate warm air from the ceiling to the floor, but the energy savings is not significant, especially in homes with forced-air heat or ceilings lower than 12 feet. When a ceiling fan operates in winter, the air movement, even when directed upward, often causes discomfort, so the thermostat may need to be turned up.
Therefore, don't operate the ceiling fan in winter.
Can you tell me the difference between an attic fan and a whole-house fan?
An attic fan ventilates only the attic by drawing in air through the attic vents. It is installed in the roof or gable. It turns on whenever the attic temperature reaches a high temperature.
Research shows that any savings in air-conditioning costs because of an attic fan generally are offset by the cost to operate the fan.
A whole-house fan ventilates the house and uses the attic vents only for discharging the air. The fan is located in the ceiling between the occupied space and the attic. It cools the house by pulling in cool outside air through open windows.
A whole-house fan can save a significant amount of energy by reducing the need for air conditioning when outside temperatures and relative humidities are in the comfort range.
What should I consider before purchasing a whole-house fan?
Several factors must be considered before making such a purchase. First, make sure a whole-house fan is appropriate for the lifestyle and climatic location.
Cooling with ventilation works best in climates with large day-night temperature differences and relatively low humidity. This type of climate is more characteristic of western Kansas than eastern Kansas. Also, be willing to use the fan on a regular basis in lieu of air conditioning to achieve a significant savings.
If a whole-house fan still makes sense, determine the size of fan the house needs. For a whole-house fan to ventilate effectively, it should make 40 air changes an hour. This means it must move two-thirds of the house volume in one minute.
Determine the volume of the house by multiplying floor area by ceiling height. Then, select a fan that has a CFM (cubic feet per minute) rating of two-thirds the house's volume. If the house is large with several floors, consider sizing the fan for just one floor.
Second, determine where to install the fan. Whole-house fans are usually mounted horizontally in the ceiling between the attic and the top floor. If the model chosen discharges through the attic, allow enough vent area for the air to escape without building up pressure. It is recommended to have one square foot of open vent area for every 750 CFM of the fan's rated air-moving capacity.
For example, a fan rated at 4,500 CFM needs six square feet of open vent area. Remember that most attic vents have insect screening, which cuts the effective area by about 50 percent.
Whole-house fans are available in direct-drive and belt-drive models. Direct-drive models have the fan mounted directly on the motor shaft. They are usually quieter and require less maintenance than belt-drive models.
Belt-drive models often use less energy per CFM of capacity than do direct-drive because the fan motor is matched more closely to the optimum fan speed. Also, belt-drive models are usually available in larger sizes.
When installing a whole-house fan, consider a variable-speed controller and a timer. The variable speed controller allows operation of the fan at different speeds, depending on outdoor temperature. The timer allows someone to turn on the fan in the evening, and then set it to automatically shut off after a certain time.
Finally, seal off the fan during the winter months to eliminate the significant amount of heated air that can be lost through the fan louvers. The simplest method is to install a whole-house fan weatherization kit available at many hardware and discount stores. The kit provides a heavy clear plastic cover and self-adhesive plastic channels to hold the plastic. The channels and plastic are applied to the house side of the fan, making seasonal installation and removal convenient.
What can you tell me about the new front-loading washing machines?
Front-loaders have been in laundromats and in Europe for years. Their new appeal here in the United States is a result of their reduced use of water and energy.
A study done by the Department of Energy (DOE) in Bern, Kan., showed water consumption fell from 41.5 to 25.8 gallons per load with use of a front-load machine.
The study was done in Bern partly because it had a chronic water shortage and the DOE wanted to determine if switching to a new style of washer would help alleviate the water-shortage problem. Monthly water usage for the town dropped 50,000 gallons per month.
In addition, energy used to heat the water is also reduced. If water is heated with electricity, annual savings would be in the range of $15 to $25 per year.
Front-loading washers are more expensive. The three U.S.-manufactured washers start at about $700, about $200 more than the better top-loading washers.
What can the ENERGYGUIDE tell me about purchasing a new refrigerator?
The ENERGYGUIDE label for refrigerators shows the estimated annual cost of energy to operate the appliance.
The figure is based on the national average rate for electricity, or about 8.5 cents per kilowatt-hour.
If the electric rate is higher than this, the cost to operate the refrigerator will be more than the price on the label; if the cost of electricity is lower, then the operating costs will be lower as well.
When purchasing a new refrigerator, it may be advantageous to buy one that has a higher initial cost.
Once purchased, keep the refrigerator operating in top condition by vacuuming the coils on the backside or bottom once a year. The buildup of dirt reduces heat transfer and lowers efficiency.
What is the cost of operating a home computer system?
At the average Kansas electric rate of 7.9 cents per kilowatt hour (kwh), a personal home computer system consisting of a processor, video display monitor, and printer will cost about 1.2 cents per hour of operation.
The energy use of each of the components per hour is processor, 30 watts; video monitor, 45 watts; and printer, 75 watts.
Actual energy use will vary with the make and model of computer. A home computer system used eight hours a day, five days a week, would cost $2.11 a month to operate at 7.9 cents per kwh.
When buying a new computer system or component, look for the Energy Star logo, which indicates that energy-saving features have been incorporated into the design of the system or component.
What should I do with my humidifier during the summer?
Clean humidifiers and store them dry during the summer months.
If it is a room humidifier, simply drain the water.
Clean out scale with a mild detergent and inspect the media element and clean or replace it if necessary. The media element is the surface, such as a foam pad or metal grid, which is kept wet to allow for evaporation.
Always unplug the humidifier before cleaning. If storing a central humidifier, shut off the power and water to the unit. Wash any scale or debris from internal parts. Again, clean or replace the media element before using the humidifier next winter.
Space Heating and Cooling
How much will I save on my heating costs if I replace my furnace with a new, high-efficiency furnace?
A new high-efficiency furnace will have an efficiency of about 95 percent.
The amount saved will depend on how efficient the existing furnace is and how much is spent on heating. If the unit is more than 10 years old, it is difficult to estimate the efficiency of furnaces without an on-site inspection.
However, there are some clues to the efficiency.
First, look at the flue. If it is made of plastic (PVC) pipe, it is already a high-efficiency furnace. Low flue-gas temperatures in high-efficiency furnaces (also known as condensing furnaces) allow for the use of PVC flues. If the flue is metal, and the unit is more than 20 years old, it probably is about 65 percent efficient or less and it is possible to save about 30 percent with an upgrade to a high-efficiency furnace. If the existing furnace is between 10 and 20 years old, its efficiency is around 75 percent and a high-efficiency furnace will save about 20 percent. If the unit was built after 1990, it will have a minimum efficiency of 78 percent and savings of about 18 percent.
To estimate the savings in heating costs, total the gas bill for a year. Subtract 12 times the July gas bill to remove the amount spent on water heating. What is left is the amount spent on heating. Multiply the existing heating costs by the percentage savings possible from above to estimate the savings.
What does it mean if a furnace has sealed combustion?
Sealed combustion is a feature found on an increasing number of high-efficiency furnaces. Air for combustion is drawn from the outdoors through a small plastic pipe connected to the furnace. A furnace without sealed combustion has to draw air from surrounding rooms.
The combustion air is replaced by air leaking around doors, windows, and other openings. This can cause uncomfortable drafts and waste energy.
In very tight homes, the natural ventilation rate may not be able to support combustion, which results in inefficient burning and backdrafting.
Sealed combustion also supplies clean air that can be critical for condensing furnaces. Indoor air may contain chlorine gas from city water and laundry products, which could cause the condensate produced by the furnace to be more corrosive than the furnace is designed to handle.
Several new furnaces I've looked at have power venting. What is this, and why is it needed?
High-efficiency furnaces cannot rely on natural draft to exhaust flue gases. This is because too much heat is removed from the gases.
Since the gases are less buoyant, energy-efficient furnaces must use a power-driven fan to force the gases out of the furnace and flue.
Power-vented furnaces require less air for combustion than natural draft furnaces because the fan guarantees the air-flow rate. This, in turn, improves combustion efficiency.
How do modern, high-efficiency furnaces vent without a chimney?
Today, most high-efficiency furnaces use a small fan to exhaust flue gases to the outside.
The fan eliminates the need for a conventional chimney. The higher efficiency of the furnace reduces the temperature of the flue gases, lowering the surface temperature of the flue pipe.
Typically, furnaces that are 78 to 82 percent efficient are vented through a steel vent pipe that is run to the outside. High-efficiency furnaces, those more than 90 percent efficient, often are vented through plastic pipe.
Is the condensate from a high-efficiency furnace harmful to a septic system?
It's unlikely that a healthy septic system will be affected by the water condensed from the flue gases of a high-efficiency furnace.
A 60,000-Btu furnace operating 50 percent of the time will produce about seven gallons of condensate a day. The condensate has a pH level of about four, which is about the same as a carbonated soft drink. However, furnace condensate is not safe to drink because of trace toxic chemicals it contains.
Will a programmable, setback thermostat save enough energy to pay for itself? If so, what features should I look for?
A programmable thermostat saves energy by automatically controlling the furnace to provide heat only when needed.
The amount of energy saved will depend on how often the furnace can be set back and the amount of the setback. An automatic thermostat also can control the air conditioner in the summer.
In general, expect to save about 10 percent with a nighttime setback of 10 degrees, and an additional five percent savings if the thermostat is also set back during the day.
If a thermostat with both a night and a day setback is desired, choose one that can change the temperature at least four times each day because four changes are required for two setback periods.
Some models simply set the thermostat back by a certain number of degrees (selectable by the operator) from the normal temperature.
Other models allow the operator to select the actual temperature desired during different periods of the day. These models give more flexibility. For example, allowing a deeper setback during the day, when no one is home, than at night.
If a daytime setback is desired, but the feature isn't needed on weekends, purchase a model that allows for a separate weekend schedule. Some models allow a different schedule each day of the week.
If a heat pump is in place, a special setback thermostat designed for heat pumps is needed. This prevents unnecessary operation of the electric heating elements during the recovery period. Some studies have shown there may be little or no savings with winter heat pump setback, but automatic operation may be desirable during the cooling season. Other features are available that may add convenience but not necessarily energy savings.
Some will remind owners when to change the furnace filter or tell how many hours a furnace has operated during a particular period. Battery backup is a helpful feature that prevents the programmed schedule from being lost during a power outage.
Above all, select a model that is simple, easy to program, and use.
Condensed instructions should be printed somewhere on the thermostat, or the operation should be easily understood from the controls themselves. Thermostats that require consulting an operator's manual to change the temperature or override the schedule can cause a great deal of frustration and often end up not being used.
What services should be included in a furnace tune up?
A thorough furnace tune up should include checking of the burners, blower and motor, controls, and chimney by a trained professional.
In the burner assembly, the heat exchanger should be inspected visually for soot, corrosion, and cracks. If there is any concern about a cracked heat exchanger, additional tests should be performed to verify that it is safe.
The burners should be removed and cleaned and the air/fuel mixture adjusted if necessary. The temperature rise through the furnace should be measured to make sure it is within acceptable limits. Excessive heat rise indicates insufficient air flow, which wastes energy and may result in poor distribution of heated air.
The blower motor should be lubricated if it is designed for lubrication. The blower should be removed and cleaned by brushing. If the blower is belt driven, the belt should be checked for proper tension and replaced if it is cracked.
Inspect the furnace's filter and replace it if necessary. The fan switch should be checked for proper on-and-off temperatures, and the high-limit switch should be checked to make sure it will shut off the gas valve should the furnace overheat.
Mercury thermostats should be checked for level installation. The anticipator should be checked and adjusted if necessary for proper burner run time.
The flue should be inspected for proper draft, corrosion, or leaks.
After inspecting, cleaning, and reassembling the furnace, the technician should run an entire cycle to verify proper operation.
I can feel air blowing out of the ductwork joints when the furnace is running. Is there something I should do about this?
Leakage from ducts to unconditioned spaces reduces the heat going to the conditioned space, thereby reducing overall efficiency.
To eliminate this problem, inspect supply and return ductwork. Tape any cracks or openings with foil tape, or seal with caulking or mastic.
To detect leaks, use smoke from stick incense or a smoke pencil. With the furnace fan running, hold the smoke near suspected leak areas. If there is a leak, there will be an obvious disturbance in the smoke. A leak in a supply duct will blow the smoke away. If the leak is in a return duct, the smoke will be sucked into the duct.
Sealing the supply and return ductwork in unconditioned areas such as crawl spaces and attics is also important.
Due to normal home construction practices, the return duct is more prone to leakage than the supply is. Sheet metal is nailed over the cavity between wall studs and floor joists. Gaps between the metal and wood, plus holes for electrical wiring and plumbing, draw air into the system.
Is it a good idea to turn off the pilot light on my furnace during the summer?
Modern furnaces do not have pilot lights, but if the unit still has a pilot light, then turning the pilot light off during the summer will save energy. If the home is air conditioned, there will be more savings on the electric bill than on the gas bill.
A typical residential gas pilot light consumes about 750,000 cubic feet of gas per month. This heat energy is simply wasted when the furnace is not operating during the summer months. However, if the house is air conditioned during the summer, the pilot light contributes heat to the house that must be removed by the air conditioner.
In dollars and cents, keeping the pilot burning during the summer months costs about $6.00 per month for the gas and about $4.80 per month for the 60 kilowatt-hours the air conditioner will consume getting rid of the heat.
The pilot also creates a draft in the chimney that causes increased air infiltration through windows and around doors, further increasing the air-conditioning load.
Some people believe that turning out the pilot light in the summer will decrease the life of the furnace. Recent tests have indicated that the possibility for damaging the furnace is minimal or nonexistent.
To extinguish the pilot light, simply follow the printed instructions on the furnace. If the directions are unclear or missing, consult a service technician or the gas utility.
If I close heating registers in some unused rooms, can I close too many?
Yes. Closing too many may cause the furnace to overheat or cause other problems. Furnaces need the cooling action of air flowing through the furnace to cool the unit. Closing off too many registers will restrict the air flow and reduce the cooling action.
Furnaces are equipped with a safety device that closes the main gas valve when the furnace overheats, but it is not a good idea to use the safety switch as a controller. No more than two out of 10 registers should be closed at one time.
After closing a couple registers, let the furnace go through a long heating period. Turn the thermostat up and check for anything unusual such as the gas valve cycling off and on. If things don't seem right, open the registers.
In extremely cold weather my furnace seems to run all the time, even though I have the setting on automatic. Will this continuous operation hurt my furnace?
No. A furnace is designed to run as long as necessary to satisfy a home's heating load. In fact, the longer it runs during each cycle, the more closely it operates to its designed efficiency. Frequent cycling caused by partial loads during mild weather or by an over-sized furnace reduces the overall efficiency of the furnace.
The colder it is outside, the longer the furnace must run to provide the heat needed to maintain a home's comfort. A properly sized furnace in Kansas will maintain an indoor temperature of 70 degrees when it's 0 degrees outside.
Therefore, it is not uncommon for the furnace to operate continuously when the temperature is below zero, but this does not harm or stress the furnace.
It is critical to keep the furnace in good operating condition during cold weather. Keep filters clean, service motors annually, and check belts for proper tightness. The furnace will not provide its maximum heating potential if it is not in optimum condition.
What does a SEER rating on air conditioners mean, and how do I compare ratings between units?
SEER stands for seasonal energy-efficiency rating. This rating measures how well an air conditioner uses energy throughout the cooling season.
The SEER is equal to Btus of cooling supplied during the year divided by kilowatt-hours of electricity consumed in a year. The higher the SEER rating, the more efficient the air conditioner will be.
For example, a unit with a cooling capacity of 24,000 BTU that consumes 2,400 kilowatts of electricity would have a SEER of 24,000/2,400, or 10. Units with high SEERs will cost more initially, but the energy savings throughout their lifetime will more than make up for the cost difference.
When comparing SEER ratings of different air conditioners, compare only those with similar capacities (Btu).
Is it cost-effective to buy high-efficiency, air-conditioning units?
Yes, if the unit serves a home or business that air conditions throughout the summer rather than on an intermittent schedule. The additional cost of the higher efficiency units can be justified from the energy savings.
The minimum seasonal energy-efficiency rating (SEER) is 10, but the Department of Energy is considering increasing the minimum to a SEER of 12.
Homeowners and business operators can justify the purchase of air conditioners with a SEER of 13 or 14 in applications where energy costs are high or the cooling season is long. In buildings used less frequently, such as churches and meeting rooms, energy savings usually won't offset the cost of the highest efficiency units.
When buying a new central air conditioner, what should I look for to ensure a high-efficiency unit that will last?
One of the best guides to the efficiency of an air conditioner unit is the seasonal energy efficiency rating (SEER).
The higher the SEER, the more efficient the unit will be. Federal legislation dictates a minimum SEER rating of 10 for central air conditioners sold in the residential marketplace. Air conditioning units are now available with SEER ratings as high as 16.
Long life and ease of service are two other important considerations when purchasing an air conditioner. One recent development in compressor design, the scroll compressor, offers a long, trouble-free life and low noise level. Scroll compressors are also more efficient than conventional compressors. Scroll compressors are often used on units with a SEER of 12 or greater. When receiving bids, be sure to ask if the unit uses a scroll compressor.
Contact at least three air-conditioning service companies in the area to obtain bids for comparison of features, warranties, and efficiency. Be sure to carefully evaluate the proposed size of the units. Purchasing a properly sized unit is critical to achieving good performance
Why is it important to properly size an air conditioner?
Today, it is recognized that accurately sized, or even slightly undersized air-conditioning equipment, will result in greater operating economy and improved comfort because the air conditioner cycles on and off less often. This reduces wear and tear on the compressor, increases efficiency, and improves humidity control.
Determining the proper size for a residential air-conditioning system calls for a cooling load analysis. This procedure takes into account the size of the home, insulation levels, roof color, orientation of windows, shading of windows, tightness of construction, and number of occupants.
However, on extremely hot days, usually less than three percent of a normal cooling season, the indoor temperature may rise or swing upward a few degrees Fahrenheit during the hottest part of the day.
This is a small price to pay for improved performance and comfort during the balance of the cooling season.
Furthermore, comfort can be easily maintained during a designed temperature swing by using a fan to create air movement and delaying activities, such as cooking, that produce internal heat gain until the air conditioner has recovered.
A cooling load analysis of a home can be performed by most heating and air-conditioning contractors or by an independent energy auditor.
What is the status of the refrigerant used in my home air conditioner? Is it being phased out like the refrigerant in my car?
Unless a central home air conditioner is relatively new, the refrigerant used is R22. It is chemically different from the refrigerant used in an auto and has only one-twentieth the impact on stratospheric ozone. Because it is not as harmful to the ozone layer, it is not scheduled for phase-out until 2020.
Some air-conditioner manufacturers are offering equipment filled with refrigerants that pose no harm to the atmosphere. The operating efficiency of these air conditioners is no higher than those filled with R22.
These products may carry a higher price, but the refrigerants will be available after the scheduled 2020 phase-out of R22.
When adding central air conditioning to an older home, what do I need to watch out for?
There are several issues to consider when adding central air conditioning to an existing heating system.
If a home has an older heating system with no provisions for central air conditioning, the ductwork may be smaller than what is required for air conditioning. Increase the fan speed to compensate for the ductwork. A larger motor often is required to achieve this higher flow rate.
In extreme cases, it may be necessary to replace the supply ductwork.
The location of the return-air registers also plays a role in comfort. In older homes, there were often no return-air registers installed on the second floor of a two-story home. It is difficult to cool the second story if this is the case. It may be necessary to install return-air ductwork.
Another consideration is the requirement for a floor drain below the furnace level. Air conditioners produce condensate when they operate. This condensate is the consequence of removing moisture from the air.
If a floor drain is not available below the level of the furnace, it is possible to purchase a small condensate pump set. For approximately $60, this set will pump the condensate to a convenient disposal site.
A final consideration is the arrangement of the ductwork at the furnace outlet. The ductwork around the furnace must leave sufficient room for the installation of the cooling coil. When installing central air, it is an excellent time to check the supply and return air ducts for leaks. Inadequate air flow across the cooling coil is the No. 1 cause for poor air-conditioning system performance.
What can I do to reduce summer air-conditioning costs? (Part I)
First, inspect the envelope of the home. The envelope is composed of the roof, ceilings, walls, floors, windows, and doors. Various opportunities exist for improving energy efficiency, such as insulation, radiant barriers, and weatherstripping. Insulation levels as high as R-38 in the attic are appropriate. It is permissible to mix insulation types, such as covering fiberglass with cellulose. Any exposed ductwork in the attic also should be sealed and insulated.
Weatherstripping and caulking reduce both heating and cooling costs. Inspect existing weatherstripping for wear and possible replacement.
In addition to caulking window and door frames, inspect for hidden cracks such as those that exist along foundations, or where exterior wiring or air-conditioning lines may penetrate the wall.
South-facing windows can be a real benefit during the heating season but can add significantly to the cooling load.
It is preferable to block the sunlight before it penetrates the window. Although a drape will delay the instantaneous solar gain, it's more effective to stop the sunlight completely by using exterior shading or reflective blinds.
Deciduous trees provide an excellent means for natural shading in the summer, yet allow exposure of the window in the winter. Removable exterior awnings can provide a similar advantage.
Unventilated attics can reach high temperatures during the summer, contributing considerably to the cooling load in the home.
Attics should be properly ventilated by having sufficient openings along the low side of the attic, such as in soffits as well as openings along the high side of the roof for exhaust.
For ventilation, have at least one square inch of free opening for every square foot of attic space. Openings should be distributed equally between the low and high sides of the attic. Remember that screens and louvers block up to 50 percent of the ventilation area.
Move air in and through the home without relying on an air conditioner. When the outdoor air is cool, yet the home is warm, a whole-house fan, which draws air through open windows and discharges into the attic, may provide all the cooling necessary.
Additional attic ventilation is necessary when using a whole-house fan.
Have one square foot of free opening for every 750 cubic foot per minute (cfm) of air moved by the whole-house fan.
Within the home, portable fans or ceiling fans can provide some cooling relief.
What can I do to reduce summer air-conditioning costs? (Part II)
Household appliances can add considerably to the cooling load in a home. Refrigerator condenser coils should be cleaned at least twice annually.
Inspect the gasket around the refrigerator door to assure that it has not worn and needs to be replaced. The cooking range and clothes dryer should be vented to the outdoors, as should exhaust fans in bathrooms.
Heat loss from a water heater adds both to water-heating costs as well as air-conditioning costs. A water heater that is warm to the touch should be insulated with a water-heater insulating jacket.
Thermostats on water heaters should be turned down to provide hot water at the tap no greater than 140 degrees.
Prepare a furnace for summer by replacing or cleaning the air filter, and lubricating, where possible, any bearings on the blower or motor. Consider extinguishing the pilot light if the furnace is equipped with a pilot. Many new furnaces use an electronic device for igniting the flame whenever the thermostat calls for heat rather than using a standing pilot light.
This will probably not result in a significant reduction in gas costs; however, the pilot does contribute a small amount of heat to the home that then must be removed by the air conditioner. Contrary to some earlier information, extinguishing the pilot light will not shorten the life of the furnace. Be sure that if the furnace is equipped with a central humidifier that it is turned off, drained, and cleaned.
An air conditioner needs adequate air flow through the condenser for the unit to operate at maximum efficiency. Plantings and fencing should be no closer than three feet to the condensing unit.
The condensing unit should be cleaned annually by carefully removing any debris from the fins of the condenser.
Consider hiring an air-conditioning service contractor to clean the condenser thoroughly, particularly if it has not received maintenance in the last two or three years.
Service contractors will use a variety of cleaning solutions to remove any buildup on the condenser fins as well as straighten any fins which may have been damaged, lubricate any exposed bearings, and check for appropriate refrigerant levels in the air conditioner.
Taking advantage of these and other opportunities should help to reduce cooling costs this summer.
My home has a whole-house fan and central air conditioner. How can I use them both for the most economical cooling?
A whole-house fan provides cooling by moving a large volume of air into and through the house, typically exhausting it through the attic.
Use the fan when the outdoor air temperature is at or below the desired indoor temperature, usually during the late evening and night hours. Use the fan at night to help create more comfortable sleeping conditions without air conditioning.
Central air conditioning cools by lowering the temperature and humidity of indoor air. When it is hot and humid outside, the house is closed up and the indoor air is conditioned. Central air conditioning and a whole-house fan should never operate at the same time.
The best strategy may be to use the whole-house fan extensively during the late spring and early fall when the demand for cooling is rarely large and extended heat waves are unlikely. Also, use the fan in the summer when temperatures and humidity are at or below normal.
When outdoor temperatures and humidity rise to uncomfortable levels, close up the house and switch to air conditioning.
In deciding what will be most comfortable, follow the weather patterns and use one system or the other for a few days. In general, avoid using both systems every day, especially during very humid weather.
The whole-house fan may significantly raise the moisture level inside a house by bringing in outdoor air. Switching to air conditioning the next day may drop the temperature, but might be less comfortable.
The most economical approach to minimize the effects of the sun's heat on a home is to use fans and the whole house fan as a first choice, and switch to air conditioning when the heat and humidity become oppressive.
Can ceiling fans effectively reduce air-conditioning costs?
Any type of fan can be effective in reducing air-conditioning costs if the air movement helps occupants feel comfortable and results in increasing the thermostat temperature setting. If the air conditioning thermostat setting is not increased, there are no savings.
The cooling effect of moving air can compensate for as much as a four-degree rise in temperature.
Keep in mind, that during the heating season, the air movement caused by the fan will still have the same cooling effect.
How can I keep my home cooler in the summer without air conditioning?
The simplest, least expensive method to keep a home cool is shading walls, windows, and the roof.
Interior shades are inexpensive and easy to install. Use pull-down or Venetian blinds in addition to regular window coverings. Window coverings should be light colored (white or beige).
There are several ways to keep a home cool without overusing the air conditioner. Of these options, install shades first. Compare utility bills before and after the installation of shades. If satisfied with the savings, stop there, but if savings are not significant, look into other options. One option to consider is exterior awnings. They are more expensive than interior shades, but would be a great way to shade south windows.
Natural shading is another way to block heat gain in summer. For example, plant broad-leafed trees on the south and west sides of the home. They shade a home in summer months and will let in sunlight during winter months when they have shed their leaves.
Certain steps will help keep a home warm in winter and will help cool it during the summer. Insulated walls and roof reduce heat gain, just as they lower heat loss in winter. As a general rule, ceiling insulation should have an R-value of 35 to 45, and walls from 19 to 27. A light-colored roof also decreases heat gain.
Use the above suggestions, coupled with circulating fans inside the home, and utility bills will be less than if air conditioning was the only cooling source.
Is it better to leave the fan running continuously with the air conditioner or to place it in the automatic position?
It is more efficient to leave the thermostat in the automatic position.
The fan consumes only one-tenth the energy of the compressor, but when it runs continuously, the fan can cost up to $30 a month.
This amount can be reduced by cycling the fan only when it's needed.
Additionally, the air conditioner will dehumidify the only air when the compressor is running. However, if the fan remains on after the compressor cycles off, some moisture on the coil will re-evaporate. This moisture must be removed during the next compressor cycle, which increases the energy consumption.
If air distribution is poor within the home or business and hot spots or very cold areas result, the fan can be run to even out the temperatures.
However, the fan should be set to the auto position when the building is unoccupied. Even better, shut the air conditioner off or raise the thermostat setting when leaving the building.
Will I save energy by turning off my air conditioner when I leave home, or am I better off just letting it run?
If gone for four hours or more, more energy will be saved by turning off the air conditioner or turning up the thermostat.
During the day, keep windows shut and close curtains or blinds on any windows that will be exposed to sunlight.
The thermal mass of the house will probably keep the indoor temperature well below the outdoor temperature, and the house should cool quickly when the air conditioner is restarted. Use a programmable thermostat or timer to turn on the air conditioner 30 to 45 minutes before the expected arrival home. If the home is still warm upon arrival, turn on a fan to create air movement.
Moving air can make the air feel about four degrees cooler than it really is.
Can I plant bushes to hide the outside of my air conditioner?
When landscaping around an outside condensing unit, remember that the air conditioner must reject all the heat from a home.
Although it is possible to plant bushes near the condenser, leave room for adequate air circulation. Without good air circulation, the temperature near the condensing unit will rise. The higher temperature will reduce the capacity of the air conditioner, causing it to work harder and provide less cooling. This could also kill the shrubbery.
If the shrubs will not form a continuous wall around the unit, plant them so that, when they mature, there will be three feet of clearance. If the shrubs will be continuous, then allow five feet of clearance.
Are there any simple checks I can perform to see if my air conditioner is operating properly?
Check a few items that should indicate if the air conditioner has problems.
First, check the two lines connected to the outside of the air conditioner. The larger on -- the suction line -- should be cool to the touch. It should not be so cold, however, that frost develops.
The smaller line -- the high pressure line -- should be warm, but not hot. It should be 20 to 30 degrees warmer than the outside temperature. In extreme cases, it will be hot to the touch, so be cautious. If this is the case, call a service technician.
Some air conditioners are equipped with a sight glass in the high-pressure line (the small line). The glass should be clear, with no bubbles visible, while the system is running. Cloudy liquid in the sight glass may indicate contamination of the system.
One final check is to measure the temperature of the air as it leaves the register. It should be 15-20 degrees cooler than the room temperature.
If the building is warm, humid, or if the ductwork is not insulated, then there may be smaller temperature differences.
These guides are not intended to eliminate the need for an annual check by a qualified service person. If problems are suspected, call for help from someone familiar with air conditioners.
Would I be better off using several window air conditioners?
Using multiple window air conditioners has both advantages and disadvantages. A distinct advantage of window units is that they can operate individually. This flexibility allows cooling only the occupied room rather than the entire house.
A central system is more convenient to operate when cooling the entire home continually, and possibly at a lower cost of operation.
If sound level is a consideration in the home, keep in mind that window units are typically noisier than central air conditioning.
In terms of efficiency, top-of-the-line central units are generally more efficient than window units.
Look at the seasonal energy-efficiency ratio (SEER) when selecting units -- the higher the SEER, the higher the efficiency under similar conditions.
Since there are positives and negatives about window units and central systems, consider personal needs and preferences before choosing a system.
What is a ton of air conditioning?
A ton is the measure of the cooling capacity of an air-conditioning unit. It is an indication of the rate that the unit removes heat from a building.
One ton of air conditioning removes 12,000 British thermal units (Btu) of heat an hour. The term was derived from the time when ice was used for refrigeration. One ton of air-conditioner cooling capacity removes the same amount of heat required to melt 2,000 pounds, or one ton, of ice in 24 hours.
Typically, residential central air conditioners will range in capacity from one and one-half to four tons. Window units will many times be rated in Btu per hour. For example, a 6,000 Btu/hr. window unit would have the capacity of one-half ton.
Other Types of Heating
Will a heat pump cost less than a gas furnace to provide the same amount of heat?
The two units are receiving their energy in different forms.
Heat pumps operate on electricity, and gas furnaces consume natural gas. Differences in fuel prices and differing efficiencies both affect the cost of delivering heat.
At current natural gas prices of about $9 per 1,000 cubic feet, a dollar's worth of natural gas can produce about 200,000 British thermal units (Btu), that is, if extracting all available energy. If a furnace is operating at 80 percent efficiency, it delivers about 140,000 Btu for each dollar spent on fuel. A high-efficiency furnace might deliver 190,000 Btu for each dollar spent.
A typical heat pump delivers about twice as much energy as it consumes. Average residential electric prices are about 7 cents per kilowatt-hour. Often electric utility companies offer lower electric rates for all electric homes. Using an electric rate of 4 cents per kilowatt-hour, a dollar will buy about 170,000 Btu. If prices are 7 cents per kilowatt-hour, the heat delivered is reduced to 97,500 Btu per dollar spent
Both energy prices and equipment performance together determine the cost of delivering heat to home.
Are heat pumps, when operating as an air conditioner, more efficient than conventional air conditioners?
The efficiency of a heat pump during the cooling season is not necessarily greater than the efficiency of an air conditioner.
Both air conditioners and heat pumps are rated according to their seasonal energy-efficiency ratio (SEER). This rating represents the seasonal cooling efficiency rather than a peak efficiency. According to the Air Conditioning and Refrigeration Institute (ARI) directory, air conditioners are available with higher SEER ratings than heat pumps.
The cost of purchasing a heat pump is usually higher than an air conditioner of the same size. The additional cost of the heat pump may be better spent by purchasing a higher efficiency air conditioner, if the primary purpose of the heat pump will be for cooling.
What is a ground-source heat pump?
A ground-source heat pump is a heating system that uses the earth as a heat source in the wintertime, and as a heat sink to eject the heat in the summertime.
Ground-source heat pumps may be either open-loop or closed-loop.
A closed-loop system circulates the same water through the loop for the heat source and heat rejection process.
The closed-loop heat source or sink may be a vertical hole or horizontal trench.
The advantage of the closed-loop system is that the water in the loop, because it is recirculating, can be treated, and the system can be used in areas where the water in the water may be contaminated or hard.
An open-loop system would be used where the water quality is good and with soft water. The advantage of the open-loop system is the initial cost is usually lower, and the efficiency is usually higher.
What would cause the radiators on the first floor to get hot while the second floor radiators stay cool on my hydronic (hot water) heating system?
Hydronic heating systems can get air trapped at the highest locations in the system. Water systems may have automatic air-bleed valves at the highest point of the distribution system to purge the system of air. If there are no bleed valves, the velocity of the water is designed to remove the air.
In some cases, radiators located higher than the distribution system may have bleed valves. Check these valves. If they are operated manually, they may need to be bled as problems arise.
Another problem may be the loss of water in the system. This is typically caused by an automatic water makeup valve, or pressure-reducing valve stuck in the closed position. This will decrease the pressure of the system, and it could cause air leakage into the system. Air leakage will increase the potential for air locking.
Unless a person has technical training in these systems, contact the heating service personnel to determine the source of the problem.