STC stands for Sound Transmission Class. STC ratings are the official way to measure noise reduction through a partition (such as a wall or in this case, a window).  It is roughly equivalent to the “dB’s” lost through a partition. For typical windows, STC ratings range from 15 to 29. Windows are typically submitted to independent labs for STC evaluation and follow the test method found in ASTM E90. STC ratings are the only way to compare products. Serious Materials, Inc. has years of experience designing and manufacturing the highest STC products for major builders throughout North America. We have numberous lab and field STC tests of our products with proven performance. Many independent lab tests are available on our websites.

What are typical STC ratings of windows?

Single pane windows typically have an STC rating of 15-20. Some older metal framed windows that don’t seal properly can be under 10. Typical STC Ratings for dual pane windows from most manufacturers range from 24 to 29, unless specified higher by the builder or homeowner. SeriousWindows with QuietGlass are available with STC 35 to STC 42, depending on the configuration. SeriousWindows with QuietGlass are not applied over an existing window, but are actual high-tech engineered windows for retrofit or new construction.  

What is the difference between SeriousWindows with QuietGlass and other “soundproof” windows?

Most “soundproof” windows are either windows which are placed inside or outside your house or building as an addition to your existing window, or are 4-track windows (where the homeowner opens 2-sets of windows each time). Many people find these alternatives unsightly and unusual looking. SeriousWindows with QuietGlass products are engineered using advanced technologies in glass, frame, and seal design that allow us to provide the highest STC windows, thus they look and operate just like regular windows. Nothing detracts from the beauty of the home.

What does STC mean in terms of actual noise reduced?

Every 10 STC points reduces noise by 50%. Let’s assume your current windows are single pane STC 20. Replacing those with STC 30 windows will reduce the noise by 50%. Replacing those with STC 40 windows will reduce the noise by 75%.

More Noise Reduction?

SeriousWindows with QuietGlass offer some of the highest STC ratings of any windows available today. As one installs windows at STC 40 for instance, the walls may become the source of more sound transmission (average walls in homes are only STC 34-39, depending on thickness of drywall and wall assembly). Fortunately, Serious Materials manufactures QuietRock soundproof drywall, which can add up to 20 STC points to existing walls. See the QuietRock website for more information.