I agree, replacing windows is the last thing to do to improve energy efficiency in homes. This option is a high cost expense, and takes years to recover the benefits of what little energy efficiency it returns. Replacing windows does not necessarily guarantee a great energy savings. If the windows are old and leaking, replacing the windows will add comfort and value to the property. However, retrieving the cost of window replacements from an energy efficiency standpoint could take ten years or more depending on the home.
All windows are create a heat loss. A single pane window has an R value of 1, whereas a double pane insulated window has an R value of 2.2. The best way to conserve energy is to provide window coverings, low E film for heat absorption and other less costly weatherization techniques. Caulking, weatherstripping, insulation and sealing leaks will go a long way to improve energy efficiency, and will return the investment dollars much quicker.
Check out hometuneup.com for more information on energy improvements and how you can find the best way to spend your energy dollars.

