Energy efficiency is important to many window buyers - but when it comes time to select a window, nearly every window is manufactured to offer excellent energy efficiency to varying degrees, usually based on cost. While each manufacturer has specific energy-efficient features that they offer, most of the windows on the market today are energy efficient. So how do you choose the right window for maximum energy efficiency within your cost range? The answer is simple - buy what you can afford for your specific situation, and ensure that it is installed correctly.

Triple glazing is good for patio doors, or windows that don’t operate. If you are opening or sliding it often, the weight on the frame can lead to wear and tear on the frame. The most extreme energy efficient window is a heavy, triple-glazed window with the maximum amount of weather stripping.

If you do go with triple glazed windows, make sure they have a ½” air space filled with argon gas. Some companies advertise a triple glaze, but only with a ¼” air space, which doesn’t give you true triple performance. That insulated airspace is absolutely necessary, especially if you have a low-e coating. Low-e coatings are designed to reflect, and contain metal. This reflects sun back on the outside or your heat on the inside. None of these coatings can stop thermal transfer - only air space can do that. Argon gas is ten times heavier than dead air, providing an extra barrier for thermal transfer.

The best value if you have a more limited budget is a vinyl window, double-glazed, with a low-e 270 I89 coating. As mentioned above, it gives you triple-glaze performance in a lighter window.