Fig. 1: Most outside noise arrives through the window, not the wall beside it.
The quick answer
Three options, in ascending order of cost and disruption. Seal the frame with adhesive tape, which is cheapest and should always come first. Hang a soundproof curtain with an MLV core, rated STC 29, which is the best value if you are not renovating. Or replace the glazing, which performs best and costs the most. Ordinary fabric curtains block light, not sound.
Traffic, dogs, street music, a busy neighbourhood. Almost all of it reaches you through windows and balcony doors rather than through the wall. A wall is a couple of hundred millimetres of masonry. The window beside it is a few millimetres of glass in a frame that may not seal. Sound takes the easier route, every time.
01 /The three options, compared
| Option | What it does | Disruption | Verdict |
|---|---|---|---|
| Seal tape on the frame | Closes the perimeter air gaps | None, DIY | Do this first, always |
| Soundproof curtain | Adds mass across the whole opening | None, hooks or screws | Best value without renovation |
| Replacement glazing | Adds mass and a sealed air gap | High, civil work | Best performance, highest cost |
| Ordinary fabric curtain | Absorbs a little high frequency | None | Blocks light, not sound |
02 /Seal the frame first
Sliding windows, worn beading and unsealed frames leave direct air paths, and sound crosses an air gap almost unimpeded. Self-adhesive EPDM seal tape around the perimeter is the cheapest intervention available and takes an afternoon. Do not expect it to solve a serious traffic problem on its own, but do not skip it either, because an unsealed frame will leak around whatever you fit in front of it.
03 /Soundproof curtains
The practical answer for most homes, and the only one that suits rented property. Our soundproof curtain is built in five functional layers: a SoundBlanket MLV core with high-density acoustic foam on both sides, faced in 350 GSM velvet.
- Rated STC 29, reducing up to 80 per cent of outside noise in real conditions.
- Velcro at the perimeter seals the curtain against the wall, which is what stops sound travelling around the edges.
- Rolls up on belts when you want the window back, and comes down without damage if you move.
- Made to your window size, with hardware supplied.
04 /Replacement glazing
A PVC frame with laminated or double glazing performs better than anything you can hang in front of a window, and it costs considerably more once installation and making good are included. Specify unequal pane thicknesses and the widest air gap you can, because two identical panes resonate together and let specific frequencies straight through. Worth doing if you are already renovating. Rarely worth doing purely for noise.
05 /What to be sceptical about
Inexpensive fabric curtains sold online as soundproof are almost always blackout curtains. They use a light-blocking coating and have very little mass, so acoustically they behave like any heavy drape. If a listing does not say what the barrier layer inside is made of, assume there isn't one.
Related reading: soundproofing windows in urban homes, and are soundproof curtains effective.
06 /Frequently asked questions
What is the cheapest way to soundproof a window?
Self-adhesive EPDM seal tape around the frame. It closes the air gaps that let sound through almost unimpeded, costs very little and is a DIY job. It will not solve a serious traffic problem alone, but every other option performs worse without it.
Do soundproof curtains actually work?
One with a mass loaded vinyl core does, because it adds real mass across the opening. Ours is rated STC 29 and reduces up to 80 per cent of outside noise. A cheap fabric curtain sold as soundproof is usually a blackout curtain and blocks light rather than sound.
Is replacing the glazing worth it?
It performs best, and it costs the most once installation and making good are included. Worth specifying if you are already renovating. Use unequal pane thicknesses and the widest air gap available, since matched panes resonate together and pass certain frequencies through.
How do I fit a soundproof curtain?
Hooks or screws above the opening, with the curtain sized to overlap the window by around two inches on all four sides. The perimeter Velcro then seals it to the wall. Seal the frame itself with tape first, since an unsealed frame leaks around anything hung in front of it.
Sonit writes about practical soundproofing for Indian homes and workplaces, with a focus on what delivers measurable results at sensible cost.
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