Ambient noise is a common problem for tenants in office buildings, apartments, and other properties in urban environments. It can be caused by street traffic, nearby trains, airport traffic, etc. If you’re bothered by incessant environmental noise, you’re likely wondering: is there anything I can do to dampen the sound

One place to start is with your windows. Today’s windows are designed to protect against ambient noise, and different types of windows are better equipped to soundproof your property. Generally, the noise-reducing abilities of your windows depend on a few factors, including glass thickness, the number of panes, and air-tightness. So how can windows help mask the sounds from the street?

How Window Noise Reduction Is Measured

Windows receive a sound transmission class (STC) rating, which is a measure of their ability to reduce exterior noise. STC ratings are one of the most common measures of sound transmission, and it’s an industry standard. If you’re interested in reducing ambient noise, you should first consider a window’s STC rating.

There are a range of ratings for the most commonly used types of windows, generally from 18 to 38. And these days, there are even windows that exceed these standards, with STC ratings into the 40s and 50s. A rule of thumb: the higher the STC rating, the better the window is at diminishing noise transmission.

If you have a property with existing single-pane windows, for instance, your windows are likely rated around 26-28. In some cases, the STC rating may even be lower than that, depending on the year that they were installed. Double-paned windows, on the other hand, which are increasingly common, are in the STC 26-33 range.

So how much sound could potentially be blocked out by replacing the dated single-paned glass. It depends on the STC rating of the existing glass. But if your windows are very old and they have an STC rating in the 18-20 range, replacing them with double-paned windows can potentially reduce noise by as much as 40 percent.

There are three factors that contribute to higher STC ratings, including glass thickness, added air space between panes, and the use of laminated glass. The highest-rated STC windows combine all three of these factors to provide a more “soundproof” window, although 100-percent soundproofing is very difficult to achieve. Fortunately, with windows with thicker glass and additional panes – i.e. triple-paned windows – you can potentially reduce 90 to 95 percent of environmental noise. For maximum noise dampening, a window would need an STC rating between 40 and 50.

Other Tips for Reducing Window Sound Transmission

Installing windows with a higher STC rating is one step you can take to diminish noise transmission. Yet, replacing existing windows can be more costly, and there are a few steps you can take before (and, in some cases, after) replacing windows. They include:

  • Repairing window seals: Existing window frames may not be properly sealed, which is a major cause of noise transmission. Patching gaps and air leaks can help to greatly reduce noise and diminish drafts, and it’s a more cost-effective solution than complete replacements. This is one of the first steps you should take, but it is often difficult for property managers to do one every window in their building(s).
  • Using sound blocking treatments: Drapes, curtains, and blinds are available that have been designed to reduce and block exterior noise. For instance, one option is acoustical blankets, which are very heavy window coverings that are made from sound-absorbing materials. These block sound, but they often block natural light, as well. Other options include sound-absorbing interior shutters, window mats and, more generally, any type of heavy-duty fabric treatments. If you enjoy or even require the natural light for environmental purposes, or if you are growing indoor plants, then these options are often not the best.
  • Installing storm windows: Storm windows are secondary windows that are mounted to the exterior or interior of a window. They effectively add another layer of glass. Commonly, they’re used to improve efficiency; the secondary layer diminishes drafts and provides a tighter seal. Additional sound reduction is a common secondary benefit of storm windows. Storm windows are more cost-effective than soundproof windows, and they can effectively reduce noise transmission by 50% or more. Like traditional windows, storm windows are available with different thickness glazing, laminates, gas fills and additional panes, which can improve the window’s sound-reducing properties.

Bottom Line

In all, windows are a major source of noise transmission. The good news is that there are some easy steps you can take to reduce noise, starting with repairing seals and installing sound-reducing treatments. For better sound-proofing, though, installing new double- or triple-paned windows with high STC ratings may be necessary to block out the majority of exterior noise.

Since 1999, Aeroseal has provided property owners on the East Coast with window solutions for combating ambient noise. If you’d like more information about how we can help with window sound-proofing, contact us today for a free consultation.