Double pane window - get it or not for a warm climate?

Question: Double pane window - get it or not for a warm climate?

M.L. of Columbus, Georgia says that, "The window company keeps trying to push double pane windows on me and I only think I need single pane. Do I need double paned?"

Answer: A double pane window, or double-glazed window, is just the way it sounds: two sheets of glass with an air or gas (krypton, argon, etc.) layer in the middle. It's not so much the extra layer of glass that's supposed to help you control heating and cooling costs--it's that air or gas layer.

A double pane window can increase your energy efficiency by almost 100%. Chugach, an Alaska-based power company (they probably know a thing or two about energy loss in that climate) says that:

...a single pane glazed window has an approximate R-value of 0.85, while a double pane glazed window has a value of 1.5 - 2.0, a low-e double pane glazed window has a 2.4 - 3.0 rating and a low-e double pane glazed window using an argon gas fill has a 2.7 - 3.6 R-value.

An R-value of 1 to 2 isn't great when you're talking walls and attics. Compare that to fiberglass batt insulation, which can have R-values of 19 or greater, and you begin to see how small it is. But within the world of windows, an R-value of 2 is pretty decent.

The fact remains: double pane windows are becoming more standard, even in parts of the country that aren't ordinarily thought of as having extreme climates.