Create an ideabook for your next remodeling project!
Browse more than 1,000,000 photos from top designers and save your favorites
There are a variety of options for your window glass, too: gas fills, heat-absorbing tints, insulated (double- or triple-glazed), low-E coatings, reflective coatings and spectrally selective coatings.
Gas fills. The most common gasses used are argon, which is relatively less expensive, and krypton, which is more expensive but has a better ability at decreasing a window's U-factor.
Heat-absorbing tints. These come in colors such as blue, green, gray, bronze or black. Tint doesn't lower a window's U-factor, but inner glass layers or spectrally sensitive coatings can be added to help with that. Gray and bronze reduce heat and light; blue and green allow more visible transmittance (VT) but only slightly reduced heat transfer.
Insulated. Double-glazed, triple-glazed, or storm windows allow space and air between panes (see the above diagram.) This lowers the U-factor as well as the solar heat gain coefficient (SHGC). In addition to air, space can also be added to lower the U-factor more.
Gas fills or low-E coatings can also be added to insulated windows to further increase efficiency.
Low-E coatings. These coatings increase a window's cost by 10 to 15 percent, the DOE says, but they can reduce energy loss by about 30 to 50 percent. The coatings reduce the U-factor but can also reduce visible transmittance unless it's spectrally selective. For hot climates or windows that get a lot of sun, the low-E coating should be on the outside of the glass. For keeping heat inside the house in the winter, the coating should be on the inside of the glass.
Reflective coatings. These coatings block solar radiation but also VT and glare. They do reduce SHGC, though, which is a plus. The DOE says that this kind of glazing works better in hot climates, but since it does increase the need for indoor lighting, the energy savings can be minimal. This type of coating is good for special applications.
Spectrally selective coatings. These coatings are great because they cut out 40 to 70 percent of the heat but still allow the light through. That means a low U-factor and SHGC but high VT. Spectrally selective coatings can be used to reduce the electric-based cooling needs of new houses in hot climates by more than 40 percent, the DOE says.
After you've made it through learning all the window jargon, you can go out and choose the style of your new windows to match the style of your house. All of these explanations won't make you an expert, but they should give you the vocabulary you need to talk to the window experts.
Are you replacing or repairing your old windows? Please tell us about them.
Replace vs. Restore: The Great Window Debate
Update Historic Windows for Charm and Efficiency
Energy-Efficient Windows: Decipher the Ratings
Contractor Tips: How to Choose and Install Windows