Should I extinguish the pilot light in my furnace during the summer months?
Yes, if you want to save energy.
"Although the volume of natural gas consumed by a pilot light in a furnace varies, it will burn approximately 700 cubic feet per month," said Richard B. Hayter, director of Engineering Extension at Kansas State University.
This not only wastes energy directly when the pilot light is unneeded, but also adds a small amount of heat to the house which, in the cooling season, must be removed by the air conditioner.
Many gas supply companies have a minimum charge in their rate schedule. "During the summer, most homes consume less than this minimum amount of natural gas," Hayter said. "Therefore, extinguishing the pilot light may not result in a dollar savings on the utility bill, but you will save energy."
When extinguishing the pilot, turn off the gas valve to the pilot and main valve to the furnace. Extinguishing a pilot light during the summer will not reduce the life of the furnace, as was once thought.
What color and type of floor tile should I use for passive solar thermal storage?
"When selecting tile to use as a floor finish material and as thermal storage for a passive solar design, you should consider more than just its energy performance characteristics," said Bruce Snead, extension specialist in residential ergy at Kansas State University.
Because you have to live in the space you have created, you should base your decision on more than just energy criteria alone.
Tile used to finish concrete floor slab should be bonded completely to the slab, which is storing most of the heat received from the sun. The finish material should either be thin and of little insuIating value, such as vinyl tile, or a dense, dark ceramic tile. Gray, red, and brown are are excellent choices in terms of absorbing solar energy.
"In general, unglazed tile is preferred because the finish reflects less light," Snead said.
You will need to seal the tile with a protective coating to prevent staining and make cleaning easy. Glazed tile is an excellent choice for a durable, easy-to-clean floor.
Glazed tile will reflect some light to the interior of the home, which actually may improve the heat distribution in some situations.
Other choices for floor coverings include paint, concrete paver blocks and thin paving brick. "Remember that the thermal storage floor material need be exposed only where it is in direct sunlight, and other floor materials can be used throughout the house," Snead said.
Can I use natural gas to drive an air conditioner?
Yes.
"In the past, the most common type of gas driven air conditioner used absorption cycle," said Richard B. Hayter, director of Engineering Extension at Kansas State University.
Although absorption air conditioners are still common and available, gas fired heat pumps are now also available for residential applications. Both units use natural gas as their source of energy rather than electricity, which is more commonly used in residential air conditioners and heat pumps. Even with the gas fired units, electricity is still used to drive any fans or pumps connected to the system.
Although most air conditioners today use electric compressors to pressurize their refrigerant, absorption units to not.
When refrigerant leaves the cooling coil in the house in an absorption unit, it is first mixed with a liquid, pumped to a higher pressure, then boiled out of this mixture by a gas flame or other source of heat, condensed and returned to the cooling unit.
"The absorption air conditioner usually has lower efficiency than its electrically driven counterpart," Hayter said. "Therefore, its popularity has declined in recent years."
Absorption units, however, are still an acceptable method of cooling where gas costs are low.
Can I use outside air to cool my building during the cooler evening hours this summer?
Yes.
"An economizer cycle is a control strategy that uses outside air for cooling when the outside air is cooler than the air in the building," said Dennis Matteson, extension specialist in small business energy at Kansas State University.
The concept is similar to a whole-house fan, except the economizer operates automatically to bring in outside air instead of running the air conditioner.
"The cooler outside air is brought in through a set of vents and dampers and exhausted through another set of dampers," Matteson said.
Because the economizer continually monitors the temperature, it can take advantage of more cooling hours than a manual outside air damper or fan.
"If the outside air temperature is warmer than the inside temperature, the air conditioning system must operate to cool the building," Matteson said.
Economizers have been used for large buildings for several years.
"In most cases, the energy savings from reduced air conditioning will offset the cost of the economizer in less than five years," Matteson said.
What are the recommended R-values for walls, ceilings, floors, and basement walls in new home construction?
"I certainly wouldn't recommend any less than R-19 floors and walls. R-38 ceilings. and R-11 basement walls," said Bruce Snead, extension specialist in residential energy at Kansas State University.
"Additional insulation in all of these areas can potentially bring heating costs down to between $100 and $200 a year when coupled with energy-efficient design."
Higher R-values usually mean a thicker building skin to accommodate more insulation, or using uncommon construction approaches. These methods, however, increase the house's price by about five percent or less, according to Snead.
"Super insulating a house gives you some protection against rising utility rates for the life of your house. It also improves the benefits of passive solar if you decide to go that route," he said.
Are my double-pane windows with a two-inch air gap more energy efficient than ones with a three-quarter inch gap?
"Sorry, but they probably aren't." said Dennis Matteson, extension specialist in small business energy at Kansas State University "The R-values of storm windows are all about equal as long as the space between the glass is five-eighths of an inch to three inches and the gas between the panes are the same. "
If the gap is less than five-eighths of an inch, there is an increase in heat from one pane to the other by conduction through the trapped air.
If it's greater than three inches, air motion caused by uneven heating will reduce the R-value, Matteson said.
"Air on the warm side of the space rises while that on the cool side falls. This motion mixes the air, transferring heat across the gap and through the glass," he added.
Are there energy efficiency standards in Kansas for new buildings?
"In the late 1970's the Kansas Corporation Commission adopted standards which still apply that require that all new residential and commercial buildings meet minimum heat loss and air conditioning or heat pump efficiencies before utilities under the commission's jurisdiction are allowed to provide permanent service to them," said Richard Hayter, director of Engineering Extension at Kansas State University.
In response to federal requirements, the commission is considering new standards for both residential and commercial buildings.
However until such time that new standards are adopted the present commission requirements still apply. According to Hayter, existing rules require that new homes may not exceed a heat loss of 35 Btu per hour per square foot of floor area in heated, finished living spaces. This is based on a given air infiltration limit and a prescribed temperature difference between inside and outside air.
Likewise, new commercial buildings must meet the same standard, except that no infiltration rate is prescribed to calculate their heat loss.
"In addition, minimum energy efficiency ratios have been prescribed for air conditioners and heat pumps installed in new buildings. Kansas has also adopted a minimum efficiency lighting standard for all new public buildings," Hayter said.
Questions regarding these energy standards should be directed to the Kansas Corporation Commission, 1500 SW Arrowhead Road, Topeka, KS 66604-4027.
Could you explain what heat recovery is?
"Heat recovery involves taking heat that is being discarded and using it to replace heat that would be furnished from another source," said Gene Meyer, extension specialist in small business energy at Kansas State University.
"As an example, some new homes are built so tightly that almost no air leaks into them. Outside air must be vented to dilute moisture and odors. During the winter, a heat exchanger can remove some of the heat from the exhaust air and transfer it to the incoming air. The exchanger is recovering heat that would otherwise have to be replaced by the furnace."
According to Meyer, heat recovery has commercial and industrial-applications, too. A common form is to use the heat rejected from refrigeration equipment to heat water or supply space heating.
"The key to a successful application of heat recovery is that there must be a real use for the heat recovered. Finding a previously unneeded heating application will not be cost effective," he said.