Double glazing or soundproof curtain: which to choose against noise
Acoustic double glazing and soundproof curtains do not play the same role: double glazing insulates more in absolute terms, around 25 to 38 dB, but it requires building work and a significant budget. A dense curtain adds a reversible barrier on the inside, with no drilling, and is particularly effective on the mid and high frequencies that standard double glazing still lets through.
The Kurtens 3-in-1 curtain, its most soundproofing model, attenuates up to 22 dB* thanks to its three technical layers and its 620 gsm fabric. Hung at the window, it complements existing glazing or works on its own where building work is impossible, particularly when renting.
What acoustic double glazing does well, and its limits
Acoustic double glazing is one of the best solutions in absolute terms, with a claimed attenuation of 25 to 38 dB depending on the glass. It acts mainly on low frequencies, the rumble of road traffic for example, and also improves thermal insulation.
Its limits are practical. It requires building work, a budget of several hundred to several thousand euros per window, and stays out of reach for most renters. Above all, standard double glazing remains permeable to mids and highs, voices, slamming doors, barking, which pass through the weak points of the window and by resonance. This is why many well-glazed homes are still bothered by certain noises.
Comparison table: acoustic double glazing or curtain
The two solutions do not share the same cost, constraint or field of action. Here is the honest comparison.
| Criterion | Acoustic double glazing | Kurtens 3-in-1 curtain |
|---|---|---|
| Attenuation | 25 to 38 dB | Up to 22 dB* |
| Frequencies treated | Mostly lows | Mids and highs |
| Building work | Yes, window replacement | None, on a rod |
| Cost | High (per window) | Moderate |
| Reversible / renter | No | Yes |
| Extra benefits | Thermal insulation | Thermal + 100% blackout |
*Data obtained under optimal test conditions. Real attenuation depends on the noise, the window and the fitting.
I already have double glazing and still hear noise
This is the most common situation, and it has a simple explanation: standard double glazing stops low frequencies well but lets mids and highs through, along with noise that bypasses the glass. Replacing recent double glazing with a reinforced model is expensive for a sometimes small gain on those specific frequencies.
The dense curtain is the most cost-effective complement here. Hung in front of the window, it adds mass and absorption on the mids and highs, and dampens reverberation in the room. According to the World Health Organization, exposure to noise, especially at night, has a direct effect on sleep and health: gaining a few decibels on the disturbing frequencies changes real comfort. To choose the right model, see our guide on how to choose a soundproof curtain.
Density makes the performance: the tiers to know
Not all curtains are soundproof. It is the mass of the fabric that blocks sound, following the mass law: the heavier and denser the curtain, the more it attenuates. Here are the reference tiers.
| Fabric density | Acoustic effect |
|---|---|
| 150 to 300 gsm | Decorative, almost no effect |
| 300 to 500 gsm | Moderate attenuation |
| 500 gsm and above | Noticeable attenuation |
| 620 gsm (Kurtens) | Up to 22 dB*, three layers |
*Data obtained under optimal test conditions.
How many decibels do you really gain
A full acoustic double glazing claims 25 to 38 dB of attenuation, the Kurtens 3-in-1 curtain up to 22 dB* on the frequencies it treats. But these figures do not read like temperatures: the decibel follows a logarithmic scale. In practice, a reduction of about 10 dB is perceived as halving the loudness you hear. Gaining a few decibels on the mids and highs, the most disturbing frequencies day to day, therefore clearly changes comfort, even when the number looks modest.
Two honest caveats. First, attenuations do not simply add up: hanging a curtain behind double glazing does not make 38 plus 22. Second, the real attenuation depends on the type of noise and the leaks around the window. This is exactly where made-to-measure matters, by removing the air gaps on the sides and at the bottom.
How much does each solution cost
The cost gap is one of the deciding arguments. Replacing a window with acoustic double glazing represents several hundred to several thousand euros per window, depending on dimensions, the frame and the fitting, not counting any co-ownership permission. It is a durable investment, but a heavy one, and not recoverable when renting.
A dense made-to-measure curtain costs the price of a curtain, with no fitting and no works. It hangs on a rod, can be removed and reinstalled elsewhere, which makes it particularly cost-effective when several windows are involved or when renting. For a tight budget or a rented home, it is the best result-to-cost solution. Discover the options in the soundproof curtains collection.
When the curtain alone is enough, when to combine both
For moderate noise, neighbours, a quiet street, footsteps or voices, a dense curtain is often enough to restore calm, with no building work. Facing a very noisy environment, a major road, a railway, an airport, combining is ideal: the double glazing cuts the lows, the curtain adds the barrier on mids and highs on the inside. The two effects add up.
To compare the thermal side of these two solutions, see also thermal curtains vs double glazing. And for the difference between soundproof and acoustic curtains, read soundproof or acoustic curtains.
The Kurtens 3-in-1 curtain against noise
The Kurtens 3-in-1 curtain is the brand's most soundproofing model. It combines three technical layers, weighs 620 gsm and attenuates up to 22 dB*, while blocking 100% of light and insulating thermally. Cut to measure to the exact dimensions of the window, it avoids sound leaks on the sides, where a standard curtain that is too narrow lets noise through. Hung on a simple rod, it works without building work and stays reversible. Configure yours in the soundproof curtains collection.
Frequently asked questions
Can a curtain replace acoustic double glazing?
Not in absolute terms: double glazing insulates more, especially on low frequencies. But a dense curtain treats the mids and highs, with no works and reversibly. For moderate noise it is often enough; facing intense noise it complements double glazing rather than replacing it.
Why do I still hear noise despite my double glazing?
Because standard double glazing stops low frequencies well but lets mids and highs through, voices and slamming. A dense curtain hung in front of the window adds mass on those specific frequencies and dampens the room's reverberation.
Should I combine double glazing and a soundproof curtain?
In a very noisy environment, yes. The double glazing cuts low frequencies on the outside, the curtain adds a barrier on mids and highs on the inside. The performances add up for optimal acoustic comfort.
What curtain weight do I need to block noise?
Below 300 gsm, the acoustic effect is almost nil. From 500 gsm, attenuation becomes noticeable. The Kurtens 3-in-1 curtain, at 620 gsm and three layers, attenuates up to 22 dB*. It is density, not colour, that makes the performance.
Are soundproof curtains effective when renting?
Yes, and it is their main advantage over double glazing. Hung on a rod, with no drilling or works, a curtain is fitted and removed freely. When renting, where changing the windows is impossible, the dense curtain is the most accessible acoustic solution.
Does made-to-measure change anything for soundproofing?
Yes. A curtain that is too narrow or too short lets sound leak on the sides and at the bottom. Cut to measure to the exact dimensions of the window, the curtain covers the whole opening and removes those leaks, which clearly improves the real attenuation.
Is a soundproof curtain cheaper than double glazing?
Yes, clearly. Where replacing windows with acoustic double glazing runs into hundreds to thousands of euros per window, with building work, a dense made-to-measure curtain stays at the price of a curtain, hung on a simple rod. With no works and reversible, it is the most accessible solution, especially when renting or across several windows.
Key takeaways
Acoustic double glazing insulates more in absolute terms but is expensive and requires building work. The dense curtain is the reversible, no-works solution that attacks mids and highs at the window, complementing existing glazing or on its own where works are impossible. For noise that persists despite double glazing, it is the most cost-effective addition. The Kurtens 3-in-1 curtain, 620 gsm and up to 22 dB*, is cut to your exact dimensions. Configure yours in the soundproof curtains collection.
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