Retrofitting soundproof windows - is that possible?


If noise becomes more and more of a problem, you can also retrofit soundproof windows under certain circumstances. What is required and what conditions must be clarified in advance, you can find out in this post.

Necessity of soundproofing

If the already installed windows let in too much noise, but otherwise have a sufficient U-value, it may make sense to retrofit the windows instead of replacing them with completely new windows.

Which sound insulation class is to be retrofitted can best be determined by several noise measurements. The standardized sound insulation classes then indicate how much of the measured sound should restrain a window.

One should also keep in mind that the measured and the subjective noise perception do not agree with each other. Even a reduction of the sound by 10 dB is subjectively perceived as only half as loud, no matter how big the noise actually is.

Foil as an alternative

In some cases one can therefore also consider retrofitting the windows with suitable soundproofing films. This may already be sufficient in many cases, and is much less expensive than retrofitting soundproof windows.

Requirements for retrofitting

However, if retrofitting is required, it must first be ensured that this is technically possible. When retrofitting, only the sash is replaced with a better sound-absorbing. The window frame remains installed. In some cases, only the discs can be exchanged.

This creates a cost advantage over a complete window replacement. The following prerequisites must be checked beforehand:

  • The existing window frame must be able to support the weight of the casement windows with sound insulation
  • the hardware system must be compatible
  • the existing sealing lamellae must be controlled (common source of problems)

Tips & Tricks

For soundproof windows, the key is proper and proper installation. It must also be ensured that the frame provides a sufficient sound-insulating effect and is sufficiently decoupled from the masonry in order to achieve good values.


Video Board: Sound Proof Windows Demonstration - single, double and retrofit / secondary glazing