Next to a lack of insulation, one of the problems homeowners face is windows that are in poor condition. As windows age, they become a major source of drafts, which lower the temperature and comfort level of a home, causing a furnace or boiler to work a lot harder.
Most older homes have sash windows, two wooden window frames that meet in the middle of the window opening. Usually, these windows have a separate storm window that attaches to the outside of the window opening. Cold air gets past these windows by going around loose storm windows and then through the gaps between the window frames and the window opening. Run your hand around the perimeter of a window on a cold windy day and you’ll feel that infiltration.
New energy efficient windows, meanwhile, stop those drafts with a number of measures: Most have two or three panes of glass in the same frame. That alleviates the need for a storm window, which also adds a nice aesthetic touch to the exterior of a home. In addition, most modern windows are filled with an inert gas, usually argon, between the glass panes. That gas serves as a better insulator than air.
New windows sometimes are also laminated with a low-E window film that slows down the transfer of radiation from the glass to the cold atmosphere outside. That prevents warm air from inside your home from escaping through the window but allows sunshine to warm your home on a cold day.
The obvious solution to poor windows is to replace existing windows with new windows. However, there are some downsides. Replacement windows are very expensive, usually several hundred dollars each. High-end units can cost thousands of dollars. The payback for replacement windows (the time it takes to recoup the initial cost of the windows through energy efficiency savings) can take decades versus years. In addition, replacement windows may not match up with the ornate wood trim found in older homes.
A recommendation by energy efficiency experts is to replace just the sashes of the window versus the entire window. Usually sashes are less expensive than windows and, more importantly, allow a homeowner to keep the look of their windows.
With such an energy efficiency improvement, a homeowner gets two things: The new sashes block the cold and the remaining window frame and trim is upgraded to better resist drafts.
The new sashes come with what is known as a channel kit. These vinyl inserts replace the cords, pulleys and weights of the old, double-hung windows. When the channel kits are inserted, an installer will also pack the cavities behind the window trim with insulation. The channel kits are also designed to stop drafts from getting past the window frames.
Before investing in replacement sashes or windows, check out some online resources. A good start is the U.S. Department of Energy’s EREN Energy Efficiency and Renewable Energy Network. Visit www.eren.doe.gov; the Efficient Windows Web site, (www.efficientwindows.org); and the Energy Star Windows Program (www.energystar.gov/products/windows/).
