Replacing plastic windows - what should be considered

Replacing windows is often advisable for energy reasons, and sometimes better noise protection is required than is available. Read this post about what to think about when replacing windows.

Life span of windows

Plastic windows usually reach the end of their service life after 20 - 40 years. At this point, many windows have to be replaced for technical reasons alone.

  • Also read - reconditioning windows
  • Also read - quality criteria for plastic windows
  • Also read - Plastic Windows: Get Spare Parts

High-quality windows that do not yet have any functional defects can in principle remain in the building as long as there are no other reasons against it. There could be different reasons.

Thermal protection as a reason for replacement

Windows that were installed before 1995 in particular usually have catastrophic U-values. Compared to modern energy-saving windows, an enormous amount of heat is lost through these windows.

Replacing the windows often pays for itself very quickly through significant savings in heating costs. How long this payback period is depends on several factors:

  • the size of the total glazed area
  • the difference in U-values between old and new windows
  • but also the type and efficiency of the heating
  • from the price of new windows and
  • of possible subsidies and tax deductions

Influence of heating

The efficiency of the heating is an often underestimated criterion. When switching to a more effective heating system (gas condensing boilers have an efficiency of more than 100 percent), there is usually a completely different amortization situation.

The price of the heating material also plays a role in the payback period. The savings with the very cost-effective biomass heating, such as wood chip heating, are significantly lower than with oil or gas as heating medium.

Optimal payback period

The possible savings after heating optimization should be such that the windows will have amortized after ten years if possible. Since the service life of plastic windows can sometimes only be 20 years, you should under no circumstances have amortization periods that are longer than this period. Then replacing the window is not really worth it.

Tips & Tricks Never blindly rely on the results of a "savings calculator" on the Internet. These computers are usually provided by a window manufacturer who, of course, would like to sell his products. Often the values for old windows are set too high or the savings are calculated overly generously. Rely on the calculation by an energy advisor who also uses the actual performance values of your heating system.