QUESTION: I plan to get energy-efficient replacement windows for my home. There are so many glass options available, that I don't know which to choose. Can you describe some of the new types of glass available?
ANSWER: There have been many significant innovations in the energy efficiency of window glass. Since glass accounts for 80% to 90% of the total window area, it has the greatest impact on reducing your utility bills and improving your comfort, summer and winter.
One of the most recent domestic glass innovations is filling the gap between the panes of thermal glass with argon gas instead of air. Argon is a naturally-occurring very dense inert gas that is totally transparent, like air. It has been used by European window manufacturers for years.
Since the argon gas is very dense, it insulates better than air. There is less movement of the argon between glass panes and therefore less heat is lost. Adding argon gas instead of air can increase the insulation value of the window up to 30%.
With argon-filled windows, the gap between the thermal glass panes can be smaller. This allows narrower windows which are more attractive and fit more houses. The argon gas also deadens outdoor noise.
Adding a special clear low-emissivity (low-E) coating to the inside surface of the glass increases energy efficiency. Almost all argon-filled windows use low-E glass. The combination of argon and low-E coatings reduce winter heat loss or summer heat gain by 75% as compared to single-pane windows.
In addition to blocking this conductive transfer year-round, the low-E coating helps block summer heat that is reflected from hot patios and driveways.
Another energy-efficient glass system uses a thin clear plastic film stretched in between the two panes of glass. The special low-E coating is applied to this piece of film. In effect, the film creates a triple-pane window without the added weight and size of true triple-pane glazing.
When comparing replacement windows, the structural quality of frame is more important than the insulation value of the frame material itself. If a lot of air leaks through the joints and gaps in the frame, even the most energy-efficient glass system will not be effective.
Don't just shop by price. A cheap window can become leaky, waste energy, and leave you very dissatisfied in the long run.
You can write to me for Utility Bills Update No. 283 showing a buyer's guide listing major manufacturers of high-efficiency replacement windows, types of glass systems (argon and low-E), frame materials, and styles. Please include $1 and a self-addressed business-sized envelope. Send your requests to James Dulley, c/o Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.
Cleaning Condenser Coils of Refrigerator
Q: I want to clean off the condenser coils in my refrigerator, but they are underneath it and not easily accessible. Can I tilt it over to the side to get the vacuum cleaner tool to the coils?
A: It is very important to keep the condenser coils clean for maximum energy efficiency. First, try to get a long brush and your vacuum cleaner crevice tool underneath to the coils.
Tilting it a little shouldn't harm it, but check with your dealer about your model. Take some precautions. First, unplug it and remove all the food. Remove the drip pan from underneath and tape the door shut.
Letters and questions to Dulley, a Cincinnati-based engineering consultant, may be sent to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.