March 2000 Edition

How To Make Windows More Energy Efficient

Our windows leak cold air in the winter months. Is there any way to make them more energy efficient?
Windows bring light, warmth, and beauty into homes and give a feeling of openness and space to living areas. They can also be major sources of heat loss in the winter and heat gain in the summer.


When air leaks around windows, energy is wasted. Several options are available to reduce the air leaks. The least expensive option is caulking and weather stripping. Next would be installing storm windows. Finally the most expensive is replacing the windows with energy efficient insulated glass.
The type and quality of the windows usually affect a window's air infiltration and heat loss characteristics. Many window types are available--all with varying degrees of energy efficiency. Some of the more common window types are fixed-pane, casement, double-hung, single-hung, horizontal sliding, hopper, and awning.
Manufacturers usually represent the energy efficiency of windows in terms of their u-values (conductance of heat) or their r-values (resistance to heat flow). If a window's r-value is high, it will lose less heat than one with a lower r-value. Conversely, if a window's u-value is low, it will lose less heat than one with a higher u-value.
Usually, window r-values range from 0.9 to 3.0 (u-values range from 1.1 to 0.3), but some highly energy-efficient exceptions also exist. When comparing different windows, you should ensure that all u- or r-values listed by manufacturers:
1. Are based on current standards set by the american society of heating, refrigeration, and air-conditioning engineers (ASHRAE).
2. Are calculated for the entire window, including the frame, and not just for the center of the glass.
3. Represent the same size and style of window.
Traditionally, clear glass has been the primary material available for window panes in homes. However, in recent years, the market for glazing--or cutting and fitting window panes into frames--has changed significantly.
Low_emissivity (low-e) glass has a special surface coating to reduce heat transfer back through the window. These coatings reflect from 40% to 70% of the heat that is normally transmitted through clear glass, while allowing the full amount of light to pass through.
Heat-absorbing glass contains special tints that allow it to absorb as much as 45% of the incoming solar energy, reducing heat gain. Some of the absorbed heat, however, passes through the window by conduction and re-radiation.
Reflective glass has been coated with a reflective film and is useful in controlling solar heat gain during the summer. It also reduces the passage of light all year long, and, like heat-absorbing glass, it reduces solar transmittance.
Window frames are available in a variety of materials including aluminum, wood, vinyl, and fiberglass.
Wood frames have higher r-values, are unaffected by temperature extremes, and are less prone to condensation, but they require considerable maintenance in the form of periodic painting.
Vinyl window frames, which are made primarily from polyvinyl chloride (PVC), offer many advantages. They are available in a wide range of styles and shapes, have moderate to high r-values, are easily customized, are competitively priced, require low maintenance, and mold easily into almost any shape. However, vinyl frames are not strong or rigid, which limits the weight of glass that can be used.
Fiberglass frames are relatively new and are not yet widely available. They have the highest r-values of all frames; thus, they are excellent for insulating and will not warp, shrink, swell, rot, or corrode. Fiberglass frames can be made in a variety of colors and can hold large expanses of glass.
Movable insulation, such as insulating shades, shutters, and drapes, can be applied on the inside of windows to reduce heat loss in the winter and heat gain in the summer. In most cases, these window treatments are more cost-effective than energy-efficient window replacements and should be considered as a budget option. Anything you do to reduce energy cost will be a benefit.


House Passes Bill Aimed At Synthetic Stucco (EIFS)

The Georgia House overwhelmingly passed legislation that would make it easier for homeowners to force builders to pay for water damage from synthetic stucco siding.
The bill, which was approved 138-27, would allow a homeowner, who uses "reasonable diligence" in keeping an eye on his property, to file a negligence claim within four years after discovering damage to his home.
Under current law, that four-year statue of limitations starts from the time a home is built. In the case of synthetic stucco, that’s long before any damage would become apparent, said Rep. Tom Bordeaux, the bill’s sponsor.
For more information see House Bill 837 or check out the website:

If you have a question, change of address, comment, home tip or would like to send Home Tips to your clients, send your letter to Home Tips, Christian Building Inspectors, Inc., 1003 Star Court, Norcross, Georgia 30093. You can E-Mail your questions to us at We reserve the right to edit questions for length.

Quote Of The Month

"A True friend is one who overlooks your failures

and tolerates your successes"

- Doug Larson

A Tip Of The Hat To:

Pat Graves

Prudential Atlanta Realty

4390 Pleasant Hill Road

Duluth, Georgia 30096

**** Thank You****