Renovation Recommendations from Heating Load Calculation - Summary
A heating load calculation is more than just a number for heating system sizing – it's an X-ray of your building. The detailed results show exactly where heat is lost and where renovation measures have the greatest effect.
Understanding the Building Envelope
Heat escapes in three ways:
- Transmission: 70-85% (through walls, windows, roof, floor)
- Ventilation: 15-25% (air exchange, leaks)
- Thermal bridges: 5-15% (connections, penetrations)
The Most Important Renovation Measures
| Measure | Savings | Cost/m² | Payback |
|---|---|---|---|
| Top floor ceiling insulation | 10-15% | 30-60 € | 3-6 years |
| Basement ceiling insulation | 5-10% | 35-55 € | 5-8 years |
| External wall insulation | 20-35% | 120-180 € | 12-20 years |
| Window replacement | 10-15% | 400-600 € | 15-25 years |
The Golden Rule
"First the envelope, then the technology!" Renovate the building envelope first, then the heating system. An optimally insulated building envelope needs a much smaller (and cheaper) heating system.