The best plastic windows - how do you find them?

The window market offers an almost unmanageable selection, even with plastic windows. Which quality criteria can be applied to plastic windows and the yardstick by which individual windows can be compared can be read in this article.

Quality of plastic windows

The most important criterion for a plastic window is certainly its longevity. It should last as long as possible, and cause low repair and maintenance costs.

This is especially ensured with plastic windows whose quality is certified. The RAL quality label, which is also recognized throughout Europe, guarantees that the window is manufactured to the highest technical standards. The so-called "Rosenheim Certificate" is a similarly high quality and recognized seal of approval for windows.

In addition, other criteria also play a role:

  • the heat protection qualities of the window, expressed by the U value
  • the soundproofing quality expressed by the soundproofing class of the window
  • Break-in security, expressed by the break resistance class of the window

Thermal insulation capability

When replacing the windows you should make sure that not only the required minimum standards are met. A U-value of 1.0 or less can be considered useful in modern buildings.

It is important to always compare the total U-values ​​(Uw-value) of the windows, and not just the U-values ​​of the glazing (Ug-value). Even with good Ug values, the Uw value can often be significantly worse than with comparable products due to the design.


Depending on which sound insulation is required, you should select the windows accordingly. A high level of sound insulation is particularly recommended when the windows are on a noisy street, or the building in a heavily noisy environment.

The selection of particularly noise-insulating windows can significantly increase the quality of living. Noise can make you sick in the long term - this applies to aircraft noise as well as street noise above a certain level.


The resistance classes for windows can vary. Experts definitely recommend protection class RC 2 for all windows on the ground floor, and RC 3 or RC 4 for poorly visible areas.

Tips & Tricks

The "best" plastic window is always the one that best suits your personal needs. This does not have to be the most efficient window at the dealer - often the requirements for sound insulation or burglar resistance are not that high. In terms of thermal insulation, however, the higher the better.

Video Board: How to Weatherize Windows with Plastic Film Insulation -- by Home Repair Tutor