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PolskiHow lucrative is the renewal of windows?
Thursday, 21st February: the “building restoration group” once again was on their way to take the measurements of the window area in the “Paul-Klee-Gymnasium (PKG)” school building. Since this work was dodgy, it took us quite a long time. Saying it more precisely we were occupied all Thursday and Friday long. However, we achieved success. Making use of a state-of-the-art laser-measuring device, we figured out a total window area of 1840m².
This value is calculated from...
- 63 glazed sliding doors at 3.1m² each = 197.5m² in total
- 44 windows at 2.2m² each = 96.8m² in total
- the remaining area of 1,544m² of ordinary glazing
These rather high figures are based on the fact that at least one side of any classroom is glazed. However, it is no wonder that we lose big amounts of energy. Furthermore, the windowpanes have partially an age of thirty years and feature a K-value of 3.5. In order to find out how much energy and money we could save if we replaced the complete glazing we got in touch with “Seele” inc, an international active company. Referring to Mr. Johann Trischberger, the responsible employee, you would have to pay 150 € per m² if you replaced the glazing but kept the frames. This would mean that the K-value could be decreased by 1.5 to 2.
The energy savings' calculation can be found subsequent:
| Energy costs: | 15,000 € minus |
| Power consumption: | 182 MWh minus |
| Replacement costs: | 276,000 € |
| Time of economization: | 18 years |
| Annual yield: | 5.48 % |
After consulting Mr. Bauer and his organization “Energiesanierung Bayern GmbH” we found out that it would be more reasonable if the frames were also replaced. This would lead to investment costs of 400 € per window and frame. However, the K-value could be decreased by 2.2 to 1.3 afterwards.
| Energy costs: | 22,000 € minus |
| Power consumption: | 267 MWh minus |
| Replacement costs: | 736,000 € |
| Time of economization: | 33 years |
| Annual yield: | 3.01 % |
As you can see, the replacement of windows would be profitable. Featuring an economical advantage on the one hand and an ecological one on the other hand the only thing we can do is to recommend these investments to the Rural District Office of Augsburg.
translator: Julian Schöler