Older windows can be a source of significant heat loss and gain in winter and summer, but replacing them with new, energy-efficient windows can be significantly expensive. Homeowners who are not ready to invest in new windows can curb energy loss by improving the efficiency of existing windows.
Improve energy efficiency by updating the windows you already own. Weather stripping and caulk can help keep air from entering or exiting around window edges. (Photo courtesy of Robert Jeffress)
Begin by checking for air infiltration or leakage around the window frames. Windows that no longer have a flush, gap-free installation can allow hot or cold air to flow freely into or out of the home. A careful inspection can uncover gaps and cracks that allow warm or cold air to leave or enter the house. One method for detecting gaps between the sash panel and the window framee is to shut the window on a piece of paper. If the paper that pulls out without tearing, the window is no longer airtight and leaks energy.
Air leaks can be corrected inexpensively with weather stripping and caulk. Installing new weather stripping seals the area around the windows, while caulking fills holes and cracks in places where different building materials join. These two materials usually pay for themselves within one year of application.
Silicone, latex, acrylic latex silicone blend and butyl rubber caulking are all useful for filling holes and cracks. First, any old caulk or sealant must be removed with a putty knife or solvent to allow the new caulk to adhere properly. The new caulk should be applied to joints in the frame and the joint between frame and wall when outdoor temperature exceeds 45 degrees Fahrenheit and humidity is low.
Weather stripping consists of narrow strips of vinyl, metal, rubber, foam or felt that are installed around the frame to seal gaps. Pressure-sensitive, adhesive-backed foam is inexpensive, easy-to-apply and can last one to three years. Reinforced foam, attached to metal or wood strips, works well against air infiltration produced by wind gusts, but it can be difficult to install.
Another easy method of preventing winter heat loss and summer heat gain is the installation of insulating shades, shutters and heavy, lined drapes. Homeowners might want to consider folding fabric shades made of cells specifically designed to trap air. These shades provide excellent insulation.