209 million windows in German residential buildings are outdated

209 million window units in German residential buildings need to be replaced with energy-efficient ones. This is the conclusion of a new study by the Federal Flat Glass Association (BF) and the Window + Facade Association (VFF).

The report, "Save more energy with new windows," finds that three outdated window types can still be found in large numbers in German residential buildings:

• Single-glazed windows - 6 million units,
• composite and box windows - 35 million units,
• windows with uncoated glass - 168 million units.

Replacing 209 million windows will save about 10.8 million tonnes of CO2 annually.

"Investing in new energy-optimised windows is a contribution to climate protection as it reduces energy consumption and thus CO2 emissions," says Jochen Grönegräs, CEO of BF.

The study recommends replacing old structures with more energy-efficient windows with Uw value of 0.95 W/(m2K) or less. The lower the U-value, the better the insulation.
In Ukraine, according to DBN B.2.6-31:2021, the minimum permissible value of the reduced heat transfer resistance of windows is Uwmin = 1.1 W/(m2K): Rqmin = 0.90 m2-K/W, temperature zone I.