Soundproof windows are what most people ask for when traffic, taxis, a neighbour’s dog or a bar down the road keeps them awake. The honest answer is that no window is completely soundproof, but the right glass, the right window style and proper sealing can take the edge off outside noise far more than most people expect. This guide explains what really works, what each option costs at Coetz™, and where to spend first.
Every Coetz™ window already comes with 6.38 mm clear laminated safety glass, which is one of the best starting points for a quieter room. You can price any size in the online estimator.
In this guide
How noise gets through a window
Sound reaches a room through the window in three ways: through the glass itself, through gaps around the opening sash, and through gaps between the frame and the wall. Thin, single panes of ordinary glass vibrate easily and pass sound straight through. Worn or missing seals let sound leak round the edges, and a frame fitted with gaps around it acts like a small open window. Fixing only one of the three helps; fixing all three makes the real difference.
Laminated glass: the first step
Laminated glass is two sheets of glass bonded to a plastic interlayer. That interlayer damps vibration, so laminated glass cuts more noise than a single sheet of ordinary float glass of the same thickness. It is also safety glass: if it breaks, the pieces stay stuck to the interlayer and the pane stays in the frame. Because 6.38 mm clear laminated glass is standard in every Coetz™ window, you get this benefit at no extra cost. See laminated glass noise reduction for how it works.
Double glazing: the biggest upgrade
Double glazing puts two panes in the frame with a sealed gap between them. The gap breaks the path of the sound, which is why double-glazed units are the usual choice for bedrooms on busy roads, flats near highways and offices near airports or railway lines. At Coetz™ double glazing is available for R1 952.50 per square metre on windows in the 30.5 mm Standard frame (top hung, side hung and fixed) and on top hung windows in the Casement 34 frame, and on most doors. See double glazed windows for the frames and prices.
Window style matters
A window that closes against a compressed seal stops more noise than one that slides past a brush. That is why top hung, side hung and fixed windows usually make better soundproof windows than sliding windows. A fixed pane, which never opens, seals best of all, so a big fixed window with a smaller top hung vent beside it is a good layout for a noisy street front. Sliding and vertical sliding windows are excellent for ventilation and space, but they are not the first choice when quiet is the goal.
Sealing the frame to the wall
Even perfect glass will not help if there is a gap between the frame and the brickwork. When the windows go in, your installer should pack the frame properly and seal all round it, inside and out. On replacement work, ask the installer to remove the old sealant and fill any gaps before the new frame is sealed. Our guide on how to install aluminium windows covers the steps.
What soundproof windows cost
Because laminated glass is already standard, the main extra cost of soundproof windows is double glazing. As a worked example, a 1 200 × 1 200 mm top hung window is 1.44 m², so double glazing adds about R2 811.60 excluding VAT to the window price. A 600 × 1 200 mm side light adds about R1 405.80. Every window size and its price is in the shop; add the double glazing as an option, or ask us to price a whole house with the estimator.
| Window | Area | Double glazing adds, excl. VAT |
|---|---|---|
| 600 × 1 200 mm | 0.72 m² | R1 405.80 |
| 1 200 × 1 200 mm | 1.44 m² | R2 811.60 |
| 1 500 × 1 200 mm | 1.80 m² | R3 514.50 |
| 1 800 × 1 200 mm | 2.16 m² | R4 217.40 |
Soundproof windows: where to start
- Bedrooms facing the road first: that is where better sleep comes from, so put the budget there.
- Choose sealing window styles: top hung, side hung and fixed windows rather than sliders in the noisiest rooms.
- Add double glazing where it counts: you do not need it on every window, only the ones facing the noise.
- Check the other gaps: air bricks, vents, gaps under doors and thin doors let sound in too.
- Keep the seals in good order: clean them and replace them if they perish; our maintenance guide explains how.
Soundproof windows room by room
- Bedrooms: top hung or side hung windows with double glazing on the street side; a fixed pane where you do not need to open the window.
- Lounges and TV rooms: a large fixed window with laminated glass and a top hung vent keeps the view and cuts the noise.
- Home offices: double glazing behind the desk makes video calls far easier on a busy road.
- Nurseries: laminated glass for safety, double glazing for quiet, and a window style that seals well.
- Bathrooms: obscure glass for privacy; noise matters less here, so standard laminated glass is usually enough.
Ordering soundproof windows from Coetz™
Measure each opening, choose the window style for each room, and add double glazing to the windows facing the noise. Every standard size is priced in the shop and made in our Laser Park workshop in 3 to 5 working days. Collect free or have the order delivered nationwide; we carry the insurance while we transport it. If you are not sure which windows need double glazing, send us the sizes and a note of which rooms face the road, and we will suggest where it is worth adding.
Fresh air without the noise
A closed window is quiet, but a room still needs air. A top hung vent opened a little lets air in while the sash still shields the opening from direct noise, and it keeps out light rain too. In very noisy places, many people keep the street-side windows closed and ventilate from the quieter side of the house at night. Fly screens on the openers let you leave a window open on warm evenings without letting insects in; see aluminium fly screens.
Other benefits of quieter windows
The same choices that cut noise help in other ways. Laminated glass blocks most ultraviolet light, which slows fading of floors and furniture, and it is much harder to break through than ordinary glass, so it adds security. Double glazing also keeps heat in during winter and out in summer, which makes a room more comfortable and can save on heating and air-conditioning; see window energy efficiency.
Soundproof windows for flats, offices and businesses
In a sectional title flat, check the body corporate rules on window style and colour before ordering; our five colours are all the same price, so it is easy to match the building. Offices, consulting rooms and studios near busy roads benefit from the same approach. For shop and office frontages, and for glass partition walls inside, MC Automations, our parent company, measures and installs; homes buy windows supply only and use their own installer.
Glass, safety and the rules
Laminated glass is also the safety glass South African building rules require near doors, floors and in bathrooms, as set out in SANS 10400-N, published by the SABS. That means a quieter window and a compliant one can be the same window. Read more in where safety glass is required.
Common myths about soundproof windows
- “Thicker glass is always quieter.” Thickness helps, but an interlayer or an air gap does far more than a slightly thicker single pane.
- “Double glazing alone fixes everything.” Not if the frame leaks round the edges; sealing matters as much as the glass.
- “Tinted glass is quieter.” Tint reduces glare and heat, not noise.
- “Any window can be made soundproof.” Windows reduce noise; they cannot make a room on a highway silent.
Soundproof windows: frequently asked questions
Are soundproof windows really soundproof?
No window is completely soundproof, but laminated glass, double glazing, a sealing window style and a properly sealed frame together cut outside noise a great deal.
What glass is best for soundproof windows?
Laminated glass is the best single pane, and double glazing gives the biggest step up. Every Coetz window already has 6.38 mm laminated glass.
How much do soundproof windows cost?
Double glazing adds R1 952.50 per square metre excluding VAT, for example about R2 811.60 on a 1 200 × 1 200 mm window.
Are sliding windows good for noise?
Sliding windows seal less tightly than top hung, side hung or fixed windows, so they are not the best choice for the noisiest rooms.
Can I add double glazing to any window?
It is available on the 30.5 mm Standard frame windows, on Casement 34 top hung windows and on most doors, but not on sliding, vertical sliding, Genius, insert or Casement 28 windows.
Do you install soundproof windows?
Our windows are supply only, so your builder or installer fits them. Seal the frame all round for the best result.
Coetz™, Unit 2, 84 Ridge Road, Laser Park, Johannesburg. Call 010 412 0062, WhatsApp 076 613 4418 or use our contact page.
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