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Windows are basically holes in your home. As such, they have a propensity to let in sound that the walls would otherwise keep out. If you live in a noisy area or are sensitive to noise, you may want to consider noise reduction windows. When considering noise reduction windows, there are generally three options available for sound attenuation (deadening). The first, and most common option is to use a double paned window, also known as an IGU or insulating glass unit. The second option is to use laminated glass. The third option is to have a wider airspace between your laminated windows and regular windows or the panes (lites) in your IGU. The fourth, and least common option, unless you live in an airport, is to use a combination of all three.
Windows are rated for their ability to deaden sound based on Sound Transmission Class (STC) testing. The resulting STC rating corresponds to what types of noise the test object will be able to attenuate. For example, if your windows have an STC rating of 48, they will be unable to block out music, but you will not hear most speech. The STC rating system only works well for relatively high-frequency air-borne noise as it is designed to block noise that is above the frequency range of human speech which is about 125 hertz, thus if you are looking for noise reduction windows to block the low rumble of traffic or heavy construction vehicles, the STC rating system will not help you. Double pane noise reduction windows are also known as insulated glass units (IGUs). They work just like they sound: one window frame holds two panes of glass separated by an air cavity. Usually, each pane is a different thickness – causing it to have a different STC rating – so that it blocks different frequencies of sound. The major problem with dual pane noise reduction windows is the same problem with regular windows: seal failure. If the seal holding the window panes in the frame fails, then there is, essentially, a crack in your window through which noise will pass. Seal failure, however, is far less common in moderate climates where there are no temperature extremes to make the seal expand and contract and finally lose elasticity and break. Laminated noise reduction windows work the same way dual pane noise reduction windows do, since they are essentially dual pane windows that fit over your existing windows. With a laminated window, just like dual pane windows, two panes of glass sit in a single frame, separated by an air cavity. The difference here is that there is a thin sheet of plastic between the window panes to absorb sound waves and attenuate noise even further. Whether the laminate film actually makes a difference is not proven. More likely, laminated noise reduction windows seem to work better because of the way they are installed. Laminated noise reduction windows fit over the entire interior frame of your regular windows – they are like window covers, but transparent. Because they are installed inside, the window seals are not subject to environmental stresses and are much less likely to crack and let noise in. Additionally, this type of installation provides a larger air space, which also helps to dampen noise. The efficacy of noise reduction windows, particularly at bothersome low frequencies, depends on the thickness of the glass in the window and the air space between panes. Thicker glass is much better at attenuating sound than thinner glass, thus the thicker the panes in your noise reduction windows, the better. As well, it is good to have a larger air cavity between the panes as this helps prevent the sound from traveling through one pane to the other. These qualities, in combination with lamination and proper seals should help keep any unwanted noise from entering your home through your windows. |
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