FAQ

There are three important elements to good soundproofing: Sufficient mass + a minimum 2-inch air gap + a good seal.

Sufficient mass – The acoustic glass we use is 1/4″ thick. It’s made from laminating two 1/8″ thick pieces of annealed glass to a flexible adhesive membrane made of polyvinyl butyl, to form one solid piece of glass. The flexible membrane keeps the glass from vibrating from sound waves and helps dissipate the energy of sound waves. The mass (weight) of the glass absorbs sound. The general rule of thumb is that the heavier the material is, the more it can absorb sound. And, of course, the opposite is true: the lighter the material, the less it can absorb sound. We use laminated glass instead of acrylic plastic because it is over twice as heavy as acrylic plastic, thereby absorbing much more sound.

A minimum 2-inch air gap – The two-inch air gap we prefer is not a magic number but a good rule of thumb when trying to stop sounds you find annoying. The bigger the gap, the more sound waves are trapped.

A good seal – The seal of our soundproofing window inserts is important because sound can act like water, seeping through openings. Our infiltration rate is less than .01 cfm/lineal foot, which meets the requirements of the  International Energy Conservation Code (IECC).

All windows block some sound, but not all windows are soundproof.

First of all, most double-pane replacement windows are designed for energy efficiency, not for sound abatement. Soundproofing requires mass + air gap + seal. Double-pane windows are made with two thin panes of glass (very little mass), held slightly apart (insufficient gap), and have spaces around the sashes so that they can easily slide up/down, side-to-side or inward for cleaning (insufficient seal for sound). The small gap is often filled with an inert gas like argon to provide resistance to energy transfer and moisture. But all gases have almost no mass (because they are gas), so they can’t physically stop sound. Due to these inherent limitations of standard replacement windows, some manufacturers now make soundproof replacement windows to tackle sound and energy issues. (See below)

Soundproof replacement windows, sometimes called triple-pane windows, are made with different designs and materials than standard replacement windows. Sometimes they use laminated glass (like our soundproof window inserts), but the air gap is limited in size because the window has to fit into the standard wall thickness. STC ratings for soundproof replacement windows are usually 38-40. The cost is usually twice that of our soundproofing window inserts, with a 48 STC rating.

In some cases, stairwells and elevators restrict the glass size we can bring to your unit. In this case, you will need an insert of two or more sections.

Traditional exterior storm windows are often quite noticeable from the outside. Most homeowners associations in Texas will not allow exterior storm windows for aesthetic reasons.

Laminated glass is not the same as double-paned glass used in standard windows. Double-pane glass is two pieces of 1/8″ glass held apart (not touching as with laminated glass) by a small gap filled with inert gas. Double-pane glass is designed for energy efficiency. The small space between the panes filled with gas acts as an insulating barrier to energy transfer. But the panes of glass can easily vibrate with sound waves because there is no flexible membrane to eliminate vibration. Plus, the gap between the panes is unfortunately too small to act as an effective sound trap. Many customers find out the hard way that double-pane is not the same as laminated glass and are very frustrated when their double-pane replacement windows do little to fix their sound problem. The STC rating of single-pane windows is ~23, and the STC rating of double-panes is only ~27, so there’s very little difference in sound reduction.