How Double Glazing Affects Room Acoustics
Have you ever spent a night in an airport hotel and wonder why you can barely hear the sound of planes taking off? Airport hotels implement several sound reduction measures, particularly the installation of acoustic windows. The Hilton Hotel close to Heathrow’s Terminal 5 Building, for example, uses a 75mm thick casement so that guests can barely hear the aircraft that fly over them.
The biggest effect of double glazing in a room’s acoustics is sound attenuation. By filtering out external noises, you can enjoy a truer acoustic feel within your own space.
In this guide, you’ll find:
Key takeaways:
- Double glazing improves a room’s acoustics by blocking out external noise.
- Glass thickness, frame type and gas affect a window’s soundproofing capacity.
- Varying glass thickness in double glazed windows filter more sound frequencies.
How Double Glazing Isolates Outside Noise
Sound is a series of vibrations. When it hits a single-glazed window, the pane vibrates and transmits sound with very little dampening effect.
In contrast, a double glazed window is made up of two panes of glass separated by compressed gas.
These are the reasons why double glazed windows absorb sound better:
- Double glazed windows are usually installed with thicker glass sheets which vibrate less and limit the amount of sound transmission.
- The compressed air between the glass panes disrupts the sound waves further reducing the level of sound that reaches the interior pane.
Some acoustic windows are filled with sulfur hexafluoride to increase their ability to reduce low-frequency noise (like the sound of traffic, aircraft, or trains).
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Factors the Affect Noise Reduction
- Gaps in the window. An air gap that is only 1% of the window’s total area can reduce sound insulation by 10 decibels.
- Glass thickness. Varying the width of glass used in the inner and outer panes increases the range of frequencies that a double glazed unit can block. It’s common to see acoustic double glazed windows use 4mm and 6mm to block different sound frequencies.
- Frames. Vinyl and steel frames let more noise in and allow more heat to escape. Timber and insulated uPVC frames are better at insulation and sound attenuation.
- Ventilation. Some sound will pass through trickle vents. However, it is necessary to install trickle vents to maintain good indoor air quality and comply with new building regulations.
- Type of glass. Some glass types have physical properties that isolate sound better. The most commonly used glass, annealed (or “float”) glass has the lowest sound-attenuating property.
Annealed glass needs to be around 20mm thick to perceptibly block external noise. Meanwhile, a double glazed window with 4mm laminated glass panes separated by a 20mm air space can reduce sound by 30 dB.
The best noise-canceling windows can reduce sound by 44 dB.
Tip: You can find a window’s noise reduction capacity on its CE marking.
Closing Thoughts
Double glazing does not improve a room’s acoustics in itself. But it filters out unwanted noise so you can enjoy a more peaceful space free of unwanted noise.
You need to allocate the right amount of budget to properly sound-proof a space. Otherwise, you will end up with a half-done window that will not provide you with the soundproofing that you need.
Energy savings will not likely pay for your investment on acoustic double glazing. But a peaceful night’s sleep is priceless.
Speaking of prices, our price comparison tool can help you get quotations to help you plan your window renovation. Compare quotes from multiple window companies so you can make an informed purchasing decision.
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