"Each degree you lower your thermostat setting will save about three percent on your heating expense," he said. "If you now keep your thermostat at 72 degrees F all of the time, you could save about six percent on your heating bills by lowering the setting to 70 degrees. You could save about 15 percent with a setting of 67 degrees.
Each degree you set the thermostat back for only eight hours every night will save about one percent on your heating cost.
"For example," Logan said, "if you now leave your thermostat set at 72 degrees all the time, you could save about five percent by setting it to 67 degrees for eight hours every night. And 10 percent can be saved by turning it down to 62 degrees every night."
The cost of the extra running time for the furnace in the morning is insignificant compared with the savings, he added.
"But with some heat pumps, nighttime setback may be counterproductive unless a thermostat designed for heat pumps is used."
Setback thermostats are becoming less expensive and are available in many stores, Logan said.
Can I upgrade my furnace to obtain the efficiencies of some of the high efficiency furnaces?
"No, you cannot simply modify or adjust your furnace to make it a high efficiency or condensing furnace," said Gene Meyer, extension mechanical engineer at Kansas State University.
The design of the heat exchanger and the materials of which it is constructed are not intended for this application.
A high efficiency furnace removes enough heat from the flue gas to cause the flue gas temperature to drop below the dew point. This type of furnace, often referred to as a condensing furnace, will have efficiencies greater than 88 percent.
January 14, 1996
Which areas in my home would benefit the most from insulation?
"Most heat lost in uninsulated homes is through the roof," said Richard B. Hayter, director of Engineering Extension at Kansas State University.
Because the attic is usually accessible, it is an area that is easy to insulate. If your attic has not been insulated, you should first install a vapor barrier directly above the ceiling. Then place insulation up to an R value of 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," Hayter said.
If you already have insulation in your attic, don't install another vapor barrier over the old insulation. You may, however, mix types of insulation, such as adding cellulose over fiber glass 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," Hayter said.
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 from 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," Hayter said.
Insulating foundation walls is appropriate only in unventilated crawl spaces. Insulation on these walls should run from the band space down the foundation wall and extend at least two feet across the floor of the crawl space. The band space 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," Hayter said.
Insulating basement walls is the next priority and is just as important as crawl space insulation when part or all of the basement wall is above grade.
"You can add furring to the wall, insulate between the furring, and add a finished surface, such as wood paneling," Hayter said. "Or you can 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. A 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.
January 21, 1996
Is there a way to use a heat pump to heat water for my home?
"Heat pumps, as well as air conditioners, can be used to generate hot water for your home or business," said Gene Meyer, extension mechanical engineer at Kansas State University.
A device called a desuperheater is installed in the refrigerant circuit. As hot refrigerant gas leaves the compressor, it goes to the desuperheater where it is used to preheat water.
The warm gas then is circulated to either the heating coil in the winter or to the heat rejection coil located outside during the summer months.
"A desuperheater on your heat pump system will slightly increase the performance rating of the equipment," Meyer said.
It does have the disadvantage of removing some of the heat during the winter that would normally go to the home, requiring the heat pump to run longer.
Desuperheaters come as options on both air-source and water-source heat pumps.
"It is not advisable for homeowners to attempt to install a desuperheater on their unit," Meyer said. The installation requires cutting into the refrigerant circuit of the heat pump system and is best left for the professional.
The vaporizer I use leaves a white dust film on furniture. What causes this, and is it hazardous to my health?
"The dust you describe comes from minerals in your water," said Doug Walter, extension specialist in residential energy at Kansas State University.
Humidifiers that atomize the water and inject it directly into the air, such as cool mist vaporizers and ultrasonic humidifiers, can cause this mineral dust build-up, because the water particles carry minerals from the water and deposit them on surfaces wherever the water droplets land.
"Calcium carbonate is one of the primary culprits," Walter said. This mineral dust is harmless to humans, but can damage sensitive electronic equipment like your stereo, VCR or computer. You can eliminate mineral dust by using distilled water, but this can cost$1 or more per gallon.
Some manufacturers of ultrasonic humidifiers now offer demineralization filters. They remove minerals from water either as it is poured into the machine or as the machine feeds the water into the transducer.
"These filters can reduce the amount of dust residue, but not eliminate it completely," Walter said.
Humidifiers which operate on the principle of evaporation by blowing air through a water-soaked filter do not cause mineral dust buildup because the minerals remain in the tank, Walter said.
January 28, 1996
Will humidifying my home lower my utility bills?
No.
"But you can keep comfortable at lower temperatures with higher relative humidities," said Richard B. Hayter, director of Engineering Extension at Kansas State University.
By lowering the indoor temperature, you will reduce the heat lost from your home, yet the net result of humidification may not reduce utility bills, he said.
Energy is required to change water from a liquid to a vapor. A portion of the energy that would otherwise be used to heat your home is necessary to evaporate water from a central or room humidifier.
Because the energy required for evaporation does not contribute to warming your home, your furnace, boiler or heat pump must run longer to satisfy the thermostat. The longer it runs, the more energy you must purchase, even though you have been able to stay comfortable at a lower temperature.
"The net result of humidifying with a central or room humidifier may not be a reduction in your utility bill and, in fact, may increase it," Hayter said.
Elevating the humidity in your home can reduce the occurrence of sore throats, dry sinuses and other upper respiratory problems associated with dry air. It also tends to tighten a house against air leaks.
"You should attempt to retain any water vapor produced in the home unless your home has excess humidity," Hayter said. "Reducing the infiltration of outdoor air by caulking and weatherstripping will not only minimize your heating bill, but also will help to retain moist air."
Routine household activities such as showering and dish washing will contribute to elevating the relative humidity. Humidity added by these activities could result in reduced heating costs.
At a room temperature of 68 degrees, it should not be necessary to raise the humidity to more than 30 percent. A room is too humid if condensation forms and persists on windows and other cold surfaces throughout the day.
What is the cost of operating a home computer?
At the average Kansas electric rate of 7.9 cents per kilowatt hour (kwh), a personal home computer consisting of processor, video display terminal and printer will cost about 1.2 cents per hour of operation, said Doug Walter, extension specialist in residential energy at Kansas State University.
The energy use per hour of each of the components is: processor, 30 watts; video display terminal, 45 watts; and printer, 75 watts.
Actual energy use will vary with the make and model of your components.
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 kilowatt hour, Walter said.