The amount of energy that escapes through American windows every winter is equivalent to all the oil that flows through the Alaska pipeline each year. That's because single-pane, unglazed windows are the most inefficient windows out there. In severe weather, a single-pane window loses heat nine times faster than a typical insulated wall.
What You Should Know
- Even during a mild winter, you can lose as much energy through one single-pane window as a 40-watt light bulb uses running seven hours a day, 365 days a year.
- Energy lost through windows can account for 25% of heating costs, and up to 30% of cooling costs.
- The biggest breakthrough in recent window technology is the low-emissivity or low-E coating, also known as Spectrally Selective. This invisible coating of inert gas molecules reflect heat back into the house but let the sunlight through easily. They cut energy loss significantly compared to windows without the coatings and are guaranteed to last for 50 years.
Easy Things You Can Do
Install new and improved windows. Specially made double-paned windows--which retain twice as much heat as single-pane windows--are now available either with an insulating air-space between the two panes or filled with a gas, such as argon.
Install superwindows. Consider the latest triple-pane superwindows, which have inert argon gas between their three panes to add extra insulation, as well as two low-emissivity coatings. The best superwindows insulate five times better than single-paned windows. Plus, today's Energy Star windows save 50% more energy than a typical 10-year-old window. For a mixed climate like we have in the Bay Area, you'll want to block heat gain in the summer and allow for it in the winter. Visit Energy Star's website to learn more.
Install storm windows if brand-new windows are not within your budget. They are particularly effective on single-pane windows and can reduce air leaks, water condensation, and frost buildup and increase a window's insulating ability.
Replace standard aluminum frames, which leak twice as much heat around the edges of the glass, with wooden, vinyl, or fiberglass frames. If you must have aluminum frames, install "thermal breaks" (rubber gaskets between inner and outer pieces).
Apply low-emissivity window films on the inside of windows to reduce heat loss up to 40%. These inexpensive clear plastic sheets can be found at hardware stores.
Install a skylight or sun tunnel to let in heat during the winter and eliminate the need for electrical lighting during the day. But be sure to insulate and cover your skylight to prevent heat loss, especially at night.
Sources: 51 Easy Ways You Can Prevent Global Warming and Save Money, by Jeffrey Langholz, PhD, and Kelly Turner, and 30 Simple Energy Things You Can Do To Save the Earth, by PG&E