Soundproof Windows: Sound Insulation Classes and Tips for a Quiet Home

Road traffic, trams or aircraft: noise is one of the biggest nuisances at home. New windows can make a real difference – if they are chosen correctly. In this guide we explain sound insulation classes, show which components really make things quieter and give tips for peaceful rooms.

Decibels and the Rw value in brief

The sound insulation of a window is stated as the weighted sound reduction index Rw in decibels (dB). The higher the value, the better. Important: decibels are a logarithmic scale. Even 10 dB less is perceived as roughly half as loud. A window with 42 dB instead of 32 dB therefore makes a clearly audible difference.

Sound insulation classes 1 to 6

Many manufacturers use the classification from the German guideline VDI 2719, which divides windows into six sound insulation classes. Modern triple-glazed windows usually already reach class 2 to 3. For homes on main roads or railway lines, class 4 or higher is advisable.

What really makes a window quieter

• Asymmetric glass build-up: panes of different thicknesses vibrate at different frequencies and dampen each other.
• Laminated glass with an acoustic interlayer: a special film between two panes adds several decibels – and increases security at the same time.
• Profile with a centre seal: an additional sealing level improves sound insulation. According to the manufacturer, the Salamander bluEvolution 82 MD system achieves up to 46 dB.
• Airtight installation: even small gaps between window and wall let sound through. An installation with permanently sealed joints is therefore essential.

Weak points: roller shutter boxes and vents

A soundproof window is of little use if there is an old, uninsulated roller shutter box above it. Make sure that roller shutter boxes or external blind covers are also sound-insulated – or opt for front-mounted systems outside the wall. Trickle vents should also be acoustic versions so that the home stays quiet and well ventilated.

Which class do I need?

• Quiet residential street: class 2–3 (30–39 dB) – modern standard windows are usually sufficient.
• Busy town street: class 3–4 (35–44 dB) with acoustic glass.
• Main road, railway or airport: class 4–5 (40–49 dB). For new buildings, national regulations may specify the requirements.

Tip: it is worth going one class higher for bedrooms – peace and quiet has a particular effect on rest there.

You will find our window systems with sound insulation data on the page PVC windows. Read more about glazing in Double or triple glazing.