Select New Efficient Replacement Windows

4. Compare typical energy cost in your climate

How window properties affect heating and cooling energy use depends to a large extent on the local climate conditions. Computer simulation tools like RESFEN can estimate the impact of window U-factor, solar heat gain coefficient (SHGC) and air leakage (AL) on the energy use of homes in various locations. The charts below are simulated examples of how different window types can affect heating energy use in a typical house in Boston, MA and cooling energy use in a typical house in Phoenix, AZ.

For pre-simulated energy use data for your climate, choose from almost 100 locations in the Window Selection Tool. This tool compares the performance of 29 window categories by showing the estimated heating and cooling energy cost for a typical 2150 square-foot house.

The Window Selection Tool allows you to quickly compare window choices for your climate but its results may not be representative of your specific home. Heat loss and heat gain through windows in a specific house depend on the window area, window orientation, shading conditions, and other factors.

5. Select the most efficient windows for your specific house»