More thermal energy is lost through windows and doors than walls: in detached houses 15%, in semi-detached houses 15–18%, and in apartment houses 19–21% of total heat loss.
Windows and doors should be kept in good condition. Their maximum maintenance interval is 15 years, but it is a good idea to check their airtightness more often. If you detect draught, you should renew the seals or ask the caretaker to renew them. In older houses, it is a good idea to seal the gap between the inner and outer frames for the winter and prevent draught by using window seal strips. The outer window frame can let out some air so that the space between the double or triple windows gets ventilated. Wooden window frames must be painted regularly so that they stay in good condition for a long time.
Windows and doors should be kept in good condition.
Like with additional insulation, the impact of new windows on the total energy consumption of a house is relatively small, and windows should be renewed for any other reason first. It is important to take care of and repair windows.
In a mechanically ventilated house, air supply windows will save energy and are a good alternative if the windows need to be replaced.
In addition, you can reduce heat loss through windows with thick curtains , for example.
