Do Double Pane Windows Block Out Noise?

Window Construction

• The amount of noise that double-pane windows block partly depends on the quality of their construction. For example, the thickness of the panes and a tight seal between the panes and the window frame affect how much noise the windows can block. It's important to find out how a manufacturer's windows are rated for noise reduction before buying them. Well-constructed windows are priced higher than windows not constructed as well.

Sound Transmission Coefficient Rating

• The weakest point for noise transmission in a home is usually at the windows, but upgrading your windows may not make a big difference in reducing noise transmission if you already have windows of decent quality. Manufacturers usually use the sound transmission coefficient (STC) scale to identify a window's ability to block sound. The higher a double-pane window's STC rating, the better it is at reducing noise transmission. Noise passing through a window is cut in half for each increase of 10 in a window's STC rating.

Pane Density

• Varying the density of panes can dampen exterior noise more effectively than not varying the density. For example, impact-resistant laminated glass helps to reduce interior noise because the laminated layer's density differs from the outer layer of glass' density, breaking up sound transmission. A window that has at least one layer of laminated glass may have a higher STC rating, such as 32 to 35, than windows without laminated glass.

Noise Sources

• The typical STC rating on standard double-pane windows ranges from 25 to 27. An acoustical engineer can evaluate how much sound enters your home through other sources. For example, a standard insulated wall has an STC rating of about 35 to 42, and the STC rating for windows should be close to that rating for the most effective noise control in the home.