Thinking about replacing your old windows, or building a home and wonder about putting in new windows? Curious about double-glazed windows?

We searched around for important questions and answers. Here they are …

We know: All About Double-Glazed Windows

What are double-glazed windows?

When most of us think of windows, we think of a single sheet of glass. Double-glazed windows have two panes of glass with a seal placed in between that creates an added layer of insulation. The space is usually filled with air, but it can be filled with a gas, such as argon.

What are the advantages of double-glazed windows?

Single-glazed windows allow both heat and cold to transfer through the window easily. That means, summer’s heat comes through the glass, as well as winter’s cold.

The double panes and insulation in double-glazed windows can cut this transfer of energy (heat or cold) in half. So, your home stays cooler in summer and warmer in winter.

What about triple-glazed windows?

Triple glazing is available and does increase the windows' insulation value. However, these windows are heavier and cost more, and are not as readily available.

Does anything else increase the insulation value of a window?

One or several layers of low-emissivity or low-E coating can be applied to window glass to help keep heat out during the summer and heat in during the winter. Low-e coatings also are available in tints.

How do I shop for new windows?

The Office of Energy Efficiency and Renewable Energy recommends you:

Look for the National Fenestration Rating Council (NFRC) label; it means the window's performance is certified.
Remember, the lower the U-value (a measure of heat flow), the better the insulation. In colder climates, a U-value of 0.35 or below is recommended. These windows have at least double glazing and low-e coating.
Look for the government’s EnergyStar label. These windows are, on average, twice as efficient as windows manufactured a decade ago and can reduce your utility bills by as much as 15%.