In residential, commercial, and mixed-use building projects, architects, engineers, and designers can be challenged by excess noise intrusion through windows, which allow far more external sound to penetrate than walls. This can compromise sleep, work, and peace of mind, and is a particular issue near urban areas, airports, railways, transit hubs, or other high traffic locations.
Building developers and buyers today are not only sensitive to noise pollution, but also have sophisticated tools available, such as an annually updated National Transportation Noise Map. Created by The Bureau of Transportation Statistics, a division of the United States Department of Transportation, this allows users to see the noise generated in particular neighborhoods.
To proactively resolve the noise problem, architecture and engineering professionals must address the fact that windows, not walls, typically account for up to 90% of external noise penetration. However, traditional single and dual pane windows are not actually designed to reduce noise.
Fortunately, design professionals are discovering how to resolve noise issues quickly and easily in new and retrofit projects by economically soundproofing the most problematic windows (facing traffic, etc.) in a matter of hours. The technology, derived from recording studios, was designed from the ground up to maximize noise reduction. Extensive testing and retesting improved the design, resulting in superior Sound Transmission Class (STC) results.
By adding soundproof windows to the building design behind only the windows that need soundproofing, architects can keep the same outside appearance for all of the windows on a project. If additional noise remediation is required in some areas after the project is complete, more can be added, based on actual noise levels.
The design of the soundproof windows also significantly reduces air infiltration, increases insulation value, and blocks the sun’s UV rays, facilitating greater comfort and energy savings.
Resolving Noise Issues
Standard single pane and dual pane windows have STC ratings ranging from 26 to 32. The higher the number, the more noise is stopped. The myth that dual pane windows are better at reducing noise derives mainly from the air leakage of older single pane windows. Although different glass has different benefits at various frequencies, dual pane glass is similar to single pane in sound transmission.
Dual pane replacement windows are designed to keep out heat and cold, but not noise. While the seals of a new window provide some noise reduction, the two pieces of glass in dual pane windows are separated by an air space and sealed into one solid glass unit. Like a drum, this causes both pieces of glass to vibrate together. This drum effect defeats the noise reduction benefit of dual pane windows.
Instead, a growing number of architectural design and engineering professionals are finding a solution to the noise problem for their clients by recommending a more modern soundproofing technology.
For example, some are turning to companies like Soundproof Windows, Inc., a company with expertise engineering windows for some of the most noise sensitive environments in the world, such as recording studios.
The company has adapted recording studio window soundproofing technology for residential and commercial properties by creating a secondary soundproofing window that installs inside, behind the existing window. The product is custom designed specifically to match – and function – like the original window. Installation is simple, straightforward, and usually can be completed in about an hour or two.
The inner window essentially reduces noise from entering on three fronts: the type of materials used to make the pane, the ideal air space between original window and insert, and finally improved, long-lasting seals. The combination can reduce external noise by up to 95% and achieve window STCs from 48 to 57.
“The first noise barrier is laminated glass, which dampens sound vibration much like a finger on a wine glass stops it from ringing when struck. An inner PVB layer of plastic further dampens sound vibrations,” explains Randy Brown, President of Soundproof Windows, a national manufacturer of window, patio door, and recording studio soundproofing products.
Air space of 2-4 inches between the existing window and the Soundproof Window also significantly improves noise reduction because it isolates the window frame from external sound vibrations.
Finally, the company places spring-loaded seals in the second window frame. “This puts a constant squeeze on the glass panels, which prevents sound leaks and helps to stop noise from vibrating through the glass,” explains Brown. These spring-loaded seals stay as acoustically sound 15 years down the road as they were on day one.
Utilizing an additional inner soundproofing window where needed on a project allows architectural professionals to stay with the primary windows they designed for the project, preserving acoustic and aesthetic integrity. The soundproofing windows can be used only where initially needed or in one area, one side, or the whole project. In all cases, the outside appearance remains the same for all of a building’s windows. Architects and engineers can change their minds later after acoustics testing and soundproof other areas that were not originally designed to be soundproofed.
When historical restorations and building conversions are required, the soundproof windows can be added without removing the original windows and glass, which is important to preservation.
Enhancing Comfort and Energy Savings
Soundproofing the windows of residential or commercial buildings can also increase comfort by reducing drafts through the existing window seals while significantly reducing energy costs.
In fact, adding the second window provides an additional layer of insulation with better insulation values than the best low-e, argon gas filled double paned window. This can reduce heating/cooling loss by 77% or more for single paned windows. The added insulation stops unwanted air infiltration around and through window seals and can reduce the heating-cooling portion of energy bills by 15-30%.
Since the approach uses laminated glass, 99% of solar UV radiation is blocked as well. This is a marked improvement over low-e glass, which typically blocks no more than 70% of the UV radiation.
When architectural designers and engineers seek to protect their clients from undue external noise intrusion in new or retrofit buildings, economically soundproofing the primary windows as needed can provide a competitive edge in design and function. This approach not only provides more peace and quiet within a home or workspace, but also reduces heating-cooling related energy costs and improves comfort.