Which flue pipe is best to use with wood-burning stoves: a double-wall, insulated metal chimney or a triple-wall, metal chimney?
"Prefabricated metal chimneys are frequently used to vent combustion gases from wood-burning stoves to the outdoors," said Bruce Snead, extension specialist in residential energy at Kansas State University.
These chimneys must not only withstand the high-temperature gases created when wood burns but also insulate the surrounding structure safely from the hazard of fire.
"If high flue gas temperatures are not maintained inside the chimney, creosote buildup will increase," Snead said.
A double-wall, insulated metal chimney uses two metal pipes, one inside the other, with insulation in between. This design results in better chimney performance by reducing the heat lost through the wall of the flue and maintaining high flue gas temperatures. This is especially important for airtight wood-burning stoves which have a potential for greater creosote buildup.
A triple-wall chimney has three layers of pipe without insulation and uses circulating air to cool the chimney.
"The air spaces between metal layers are connected at the bottom of the flue and vented to the outside at the top, setting up a natural convection air flow induced by the temperature difference between the hot inner surface and cold outer surface," Snead said.
This not only reduces the fire hazard to surrounding materials but also cools the innermost pipe, leading to substantial condensation and reduction in the draft that would usually occur through the flue. The increased condensation and reduced draft are unsatisfactory for most wood stove installations.
What is a ground-coupled heat pump?
"A ground-coupled, or earth-coupled, heat pump uses the earth as a heat source for winter heating and as a heat sink for summer cooling," said Doug Walter, extension specialist in residential energy at Kansas State University.
The advantage of earth-coupling is the improved operating efficiency of the heat pump.
Because the earth maintains a fairly stable temperature of 55 to 65 degrees at about six feet below the surface, the ground-coupled heat pump can extract heat from the soil, which is warmer than typical winter air temperatures, even though the soil temperature will continue to drop through the winter.
"In the summer, the earth provides a much more effective heat sink than hot air," Walter said.
Ground-coupling is usually achieved by circulating water through a coil of piping buried in the earth. Or, if the water level is high enough, by pumping water out of a well, through the heat pump. and then back into another well, according to Walter.
What is a double envelope, solar house?
What should I look for when buying replacement windows and doors?
Windows and doors are the most frequently used items in the exterior shell of your home, and their durability, energy efficiency and maintenance are all important concerns.
In windows, look for good tight construction with integral weatherstripping between the sash and frame," said Bruce Snead, extension specialist in residential energy at Kansas State University. "Replaceable weatherstripping is an advantage."
Operating hardware should be durable. If the windows have steel or aluminum frames, check to see if thermal breaks are used to reduce the possibility of condensation.
"We recommend double-glazing or insulating glass here in Kansas," Snead said.
Energy efficiency ratings for windows may include both an air infiltration rate and a U-value, which is equal to 1 divided by the R-value. These figures are based on laboratory tests of standard units and., in general, the lower the U-value and air infiltration rate, the better the window.
"Be wary of advertisements using energy-saving claims without providing actual numbers based on standard test procedures," Snead said.
For replacement doors, a good unit will come prehung for easy installation. They will also have integral weatherstripping at the head and jambs and adjustable weatherstripping at the sill.
"Steel-faced doors with foam cores will have higher R-values than solid wood doors, but thermal breaks between the inner and outer skin are essential," Snead said.
Can I place the energy-saver switch on my refrigerator in the energy-saver position and just leave it?
"The energy-saver switch on refrigerators and freezers controls a small heating element in the door frames that is used to prevent moisture from condensing on the outside surfaces of the refrigerator," said Gene Meyer, extension specialist in small business energy at Kansas State University.
Moisture condenses around the doors of the refrigerator during warm, humid times of the year. During the cool, dry part of the year, you may place the switch in the energy-saving position to shut off the heaters.
If condensation begins around the door openings, place the selector switch in the normal position. When weather conditions change, try placing the switch in the energy-saving position and check for moisture.
"You may be able to leave the switch in the energy-saving position all year if your home is air-conditioned," Meyer said.
I recently had a heat pump installed in my home. The air from the vents is about 85 degrees, which seems cooler than other heating systems. Is this typical?
"The air temperature coming from your heat pump is well within the range of what could be expected," said Gene Meyer, extension specialist in small business energy at Kansas State University. "The temperature of the air leaving the vents supplied by a heat pump will be below that supplied by a conventional furnace."
Because the air is between 85 and 100 degrees and is moving, it may seem cool to anyone sitting directly in front of the vent.
"Do not, however, equate the temperature of the air with the total heat provided," Meyer said.
Properly sized heat pumps will efficiently heat your home. Some who have recently installed heat pumps may have been accustomed to a conventional forced air heating system. The delivery air temperatures from a forced air heating system is higher than from a heat pump.
"I suggest you give yourself time to become accustomed to the operation of your heat pump," Meyer said.
What will adding a skylight do to my heating and cooling bills?
"Properly used, a skylight that faces south and is double-glazed can be an energy benefit for your home," said Bruce Snead, residential energy specialist at Kansas State University. "If the roof has a steep slope, it can collect quite a bit of solar heat in the winter."
A skylight that opens can release warm air and help set up cooling convection currents during the summer. Free light is another advantage.
Because skylights collect heat year round, they should be shaded in the summer, preferably by outdoor screens or vegetation, or by shades operated from inside. In addition, movable insulation would help reduce heat loss on winter nights, Snead said.
"A sunspace or greenhouse may be the best place for skylights because in those areas it's easier to control their effects on the main part of the house," Snead said.
Last fall I installed storm windows, caulking and weatherstripping. Now I am getting condensation and frost on my windows. Why?
"Your moisture problems are probably a result of both the weatherization and the weather," said Gene Meyer, Kansas State University extension specialist in small business energy. "Unusually cold weather causes windows to be colder than normal. Tightening up your house keeps more moisture from cooking and other activities inside. Both circumstances encourage condensation."
To reduce the moisture level in your house, Meyer recommended using exhaust fans in the bathroom and kitchen. Even covering pots and pans with lids when cooking will help.
Unvented heaters also contribute to the problem. As part of the burning process, they release moisture into the air. If you are using unvented heaters, you should always leave open a window to dilute the products of combustion, including water vapor, he said.
"Condensation that appears on windows in the early morning or late evening but disappears during the day does not indicate the humidity is too high. But if it persists throughout the day, you may have a problem," Meyer said.
I have good, tightly fitting storm windows over the primary windows in my home. Would it be cost effective to install interior storm windows as well?
"Although a third glazing would certainly save energy, it may not save enough to justify the cost of the interior storm windows, especially if the windows are covered with heavy. closely fitting drapes or curtains," said Richard Nelson, extension specialist in energy at Engineering Extension, Kansas State University.
"Interior storm windows" or inner glazings are usually thin plastic sheets designed as a low cost alternative to exterior storm windows.
If you already have exterior storm windows, the cost effectiveness of interior storm windows is reduced, especially if your exterior storm windows are in good shape because they will not allow much infiltration.
"The cost effectiveness also depends heavily on the cost of the interior storm windows," Nelson said.
Some plastic sheets designed primarily to cut infiltration losses are inexpensive and probably would be cost effective. More expensive decorative window treatments are difficult to justify strictly on economics.