Window renovation – more comfort in old buildings

At the latest when it starts to get uncomfortable on cold days, it’s time for a window renovation. However, it is often worth renewing windows much earlier in older buildings. Because the best insulation on the facade or roof is of little use if there is heat loss through old windows. In addition, modern windows not only have a higher insulation value, but also resist theft attempts longer. Even in old buildings, it is not always necessary to completely replace all windows when renovating windows. Worn seals or insufficient glass can be replaced and that alone can work small miracles. However, especially in the case of older wooden windows, it is worth considering whether the repairs really pay off or whether, in the long run,

U-value improvement through window renovation

An individual measure in the context of the refurbishment of old buildings to an energy efficient building is the renovation of windows. A large part of the heating energy in old buildings is lost through windows. Therefore, window renovation should be one of the first measures to reduce energy consumption. Minor repairs may be sufficient depending on the condition, year of construction and window type. If the windows of the old building still have single glazing, the new sealing tapes alone do not bring great advantages. Because the energy loss of a single-glazed window is up to five times greater than that of a double-glazed one. Triple glazing exceeds these values. Window manufacturers indicate the heat transfer coefficient as a U value. In general, the lower the U value, the lower the U value. less energy loss through the window. While single glazing hardly drops below a U value of 5 W/(m²K) and box windows halve this value, double glazing has a low heat transfer coefficient of just over 1.1 W/( m²K). In triple glass it is still significantly smaller. For comparison purposes, here is a small overview of the types of windows currently used in older buildings with their average U-values ​​in W/(m²K), which may vary depending on the year of construction:

What simple options are there for window renovation?

If the window frames are still in good or very good condition, it is not necessary to install new windows immediately. A window renovation can also consist of maintenance, simple repair work or replacement of individual parts. In any case, it is advisable to ask an experienced window installer about the possibilities for improving the window density before proceeding with its replacement.

Renew sealing tapes

Conservation of old windows can be considered if the window frames are in good condition. For example, if the windows have good plastic frames and only the sealing tapes are brittle, these can be replaced at low cost. If well-maintained wooden windows do not already have seals, the window manufacturer can incorporate them later by milling them. Both are measures that can do a lot, depending on the state of the existing window.

additional glass

Buildings classified as monuments and which do not have double glazing are an example of when it makes sense, and is sometimes the only alternative, to simply replace the glazing instead of the entire window. If the window frames are strong enough, a fixing panel can insulate a single-glazed window both energetically and acoustically. On average, the U value can be improved by up to 40%.

glass replacement

Alternatively, window renovation can be carried out by replacing the glass, provided that the window frame still meets the requirements of the Energy Saving Ordinance. With this type of window renovation, theft protection can also be improved by using laminated protective glass or locks on the window handles.

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I am a graduate of journalism and social communication at the University of south Australia and a "fresh" graduate of media creation at the University. I am interested in architecture, urban planning and interior design. For several years, I have been cooperating with clients from the construction industry, I advise, help in choosing my dream home and share my knowledge with the Extrados guide zone.