If you're shopping for new windows, you have likely debated over the size and the material of the frames, but have you spent any time considering what type of glass you want? Although most window panes may look similar, there is a world of difference between those glass types. Some types of glass are kinder to the environment than others and can even help save you money on your monthly utility bills.

Glass types to choose to save energy (and energy dollars)

The energy efficiency of window glass is measured by both a U-value and a solar factor. The U-value measures the interior heat lost via the window. The lower the U-value, the more efficient the window. The solar factor measures how well the window reflects the sun's UV rays. This measure is either a zero or a one, with zero being the most energy-efficient. In most parts of the country, you'll need windows that address both issues.

1. Double and triple-pane glass. If you're shopping for replacement windows, you're likely getting rid of single pane windows that offer just one barrier between you and the elements outdoors. Two and three-pane glass windows can be made with non-toxic, invisible argon or krypton gas between the panes for extra insulation. In addition, both types of windows can be made with low-e coating.

2. Low-E glass. So-called low-E glass has an invisible coating of silver oxide on it that helps to block the sun's UV rays from entering your living spaces and forcing your cooling system to work harder to keep your rooms comfortable on hot, sunny days. Reducing your need for air conditioning helps to keep your electric bill low and prevents using unnecessary energy. You can save up to 25 percent on your electric bill by choosing low E. Low-E glass also helps to prevent fading to your upholstery, rugs and other household objects.

3. Other window glazing. Low-E glass is just one of several types of window glazing (tints) you can opt for when you order your windows. Other glazing products you can choose include Heat Mirror, which is made with a sheet of low-E film suspended between the glass panes.

While the environment may not be the first thing that pops into your mind when you go shopping for new windows, choosing eco-friendly glass can both reduce your family's carbon footprint and help to keep your utility bills in check. For more information on glass, contact a retailer such as Park Glass Inc.