Windows in Existing Homes
             Should You Replace Your Them?

Windows serve many purposes and we ask our windows to do a lot. Ideally they would:

• Manage heat gains and losses
• Provide daylighting
• Provide a view, privacy and limit glare
• Provide shading and sun control
• Create thermal comfort
• Create condensation control
• Ultraviolet control
• Acoustic control
• Energy requirements

Many of the new windows available can do all these things, but is the cost worth it to you? As with many things in life....it depends.

According to the Whole Building Design Guide, an older single-pane window has an insulation factor of R1. A modern double-glazed window offers R3 insulation. Yet if the walls of a historic building have an R-value in the teens, "taking a window from R1 to R3 will not provide sufficient energy savings to offset the cost of replacement windows and associated waste," according to the guide. The primary cause of air infiltration can be addressed with jamb insulation, weather stripping, and trim repair.

Depending on the climate and the window cost, the payback period for replacement windows can be as long as 20 to 30 years.

John Seekircher, a restoration window specialist, has a prospective not often heard, "We call them replacement windows because you keep replacing them.. When modern windows, with their high-tech seals, eventually fail-and they will-the result tends to be catastrophic failure. You don't repair them. You replace them. Anyone who doesn't see something amiss in replacing century-old windows with "environmentally responsible" windows that will be junked and replaced every decade or two is suffering from an irony deficiency."

There is an option for older windows most people aren't aware of, low-e storm windows. Although many window suppliers are unfamiliar with the product, low-e storms can be ordered. According to a recent study, the payback period for installing low-e storm windows is just over 4 years.

If your windows are in truly bad shape, you are adding an addition or you plan on living in your home for years and have decided you want all the features new windows have to offer, you need to know how to compare features to get the best windows for your site, architectural style and budget.

Click here to learn about U Value, SHGC (solar heat gain coefficient), VT (visible transmittance) and AL ( air leakage). These terms will be used by window manufacturers.

To learn which windows will save you the most money over the long haul visit:  http://www.efficientwindows.org/  Click on the Windows Technologies tab to learn about the many window options. The Window Selection section is very useful, as well.

Print out the Energy Code Compliance Guide to window selection in NC to take to the showroom when shopping for windows. Find it here: http://www.efficientwindows.org/codes2006/NorthCarolina.pdf

Alas, there are no self cleaning windows...yet.