Save with Energy Efficient Windows in Colder Climes

Whether you are selecting windows for a new home, or trying to cut down on energy costs with energy efficient windows for your old house, selecting windows can be confusing. Window technology has changed dramatically in recent years, with advances in both energy efficient glass and window assembly. To keep your home insulated from the cold, and to save money on heating bills, here are some tips for selecting energy efficient windows.

Modern Improvements
Today's windows are constructed of energy efficient glass that insulates almost four times more effectively than windows 20 years ago. This is due to several important energy-saving features. First, multiple layers of glazing drastically increase the insulation properties of the window. But even double-glazed windows can lose large amounts of heat with a too-thin air space between the panes of the window. A thicker air space will increase the performance of energy efficient glass. Finally, e-coatings are applied to the window, reflecting heat back into your home while still allowing light to pass through.

A Guide to Window Ratings
There are three key window ratings that you should use to gauge the energy-efficiency of window: the U-factor, the solar heat gain coefficient, and the air leakage.

• he most important window rating, the U-Factor, is a measure of the heat loss created by a window. The lower the U-Factor, the better a window will resist the flow of heat and keep the warm air inside where it belongs.
• The solar heat gain coefficient (SHGC) is the fraction of the solar energy that passes through the window. Energy efficient windows have a SHGC window rating between 0 and 1, depending on the local climate.
• The last window rating you should keep in mind is the air leakage value. Heat loss and gain can occur through cracks in the window structure. The lower your air leakage, the less heat will be lost through cracks in the window assembly.