Insulation & Air Sealing

You can reduce your home's heating and cooling costs by as much as 30 percent through proper insulation and air sealing techniques, the U.S. Department of Energy (DOE) states. The following techniques also will make your home more comfortable.

  • Remember that new windows must be installed correctly to avoid air leaks around the frame. Look for a reputable, qualified installer.
  • In temperate climates with both heating and cooling seasons, select windows with both low U-values and low solar heat gain coefficiency (SHGC) to maximize energy benefits.
  • Select windows with air leakage ratings of 0.3 cubic feet per minute or less.
  • Remember, the lower the U-value, the better the insulation. In colder climates, a U-value of 0.35 or below is recommended. These windows have at least double glazing and a low-e coating.
  • When you're shopping for new windows, look for the National Fenestration Rating Council label; it means the window's performance is certified.
  • Installing new, high-performance windows will improve your home's energy performance. While it may take many years for new windows to pay off in energy savings, the benefits of added comfort and improved aesthetics and functionality may make the investment worth it to you.
  • Apply sun-control or other reflective films on south-facing windows to reduce solar gain.
  • Install awnings on south- and west-facing windows.
  • Close curtains on south- and west-facing windows during the day.
  • Install white window shades, drapes, or blinds to reflect heat away from the house.
  • Repair and weatherize your current storm windows, if necessary.
  • Install exterior or interior storm windows; storm windows can reduce heat loss through the windows by 25 percent to 50 percent. Storm windows should have weatherstripping at all moveable joints, be made of strong, durable materials and have interlocking or overlapping joints. Low-e storm windows save even more energy.
  • Keep windows on the south side of your house clean to let in the winter sun.
  • Close your curtains and shades at night; open them during the day.
  • Install tight-fitting, insulating window shades on windows that feel drafty after weatherizing.
  • You can use a heavy-duty, clear plastic sheet on a frame or tape clear plastic film to the inside of your window frames during the cold winter months. Remember, the plastic must be sealed tightly to the frame to help reduce infiltration.
  • Conduct an energy audit of your home to find air leaks and to check for the proper level of insulation. Common sources of air leaks include cracks around windows and doors, gaps along baseboard, mail chutes, cracks in brick, siding, stucco or foundation, or where any external lines (phone, cable, electric and gas) enter the home.
  • To test for air leaks on your own, on a windy day, hold a lit candle next to windows, doors, electrical outlets, or light fixtures to test for leaks. Also, tape clear plastic sheeting to the inside of your window frames if drafts, water condensation or frost are present.
  • Plug air leaks with caulking, sealing, or weather stripping to save 10 percent or more on your energy bill.
  • Adequate insulation in your attic, ceilings, exterior and basement walls, floors and crawlspaces, as recommended for your geographical area, can save you up to 30 percent on home energy bills.
  • Installing storm windows over single-pane windows or replacing them with ENERGY STAR windows can reduce heat loss from air leakage, and reflect heat back into the room during the winter months to save even more energy.
  • In cold climates, ENERGY STAR windows can reduce your heating bills by 30 percent to 40 percent compared to uncoated, single-pane windows, according to the Efficient Windows Collaborative.
  • Close fireplace dampers when not in use. A chimney is designed for smoke to escape, so until you close it, warm air escapes.

This article originally appeared in the 01/01/2007 issue of Environmental Protection.

Featured Webinar