Save CO₂ and Improve Energy Efficiency
Upgrading existing wooden windows is a sustainable and cost-effective alternative to complete window replacement. Instead of disposing of functioning windows, we modernize existing structures to meet current technical, energy-efficiency, and security standards.
With targeted measures, we improve thermal insulation, burglary protection, airtightness, and service life — with significantly lower CO₂ emissions compared to installing new windows.
Example: Upgrading a Wooden Window (Spruce 68 mm)
Initial situation:
Spruce wooden window, frame thickness 68 mm, double-leaf, dimensions 1200 × 1600 mm.
Our modernization measures
✅ Replacement of glazing with thermal insulation glass Ug = 0.7 W/m²K
✅ Bonding between glass and sash rebate for increased stability and airtightness
✅ Milling in an additional overlap seal to prevent drafts and heat loss
✅ Replacement of fittings with upgrade to RC2 burglary protection
✅ New gearbox for the second opening sash
✅ Professional wood treatment and surface protection
The existing window is preserved — but technically upgraded to a modern performance level.
Energy and CO₂ Savings – Calculation Example
Window area: 1.92 m²
| Condition | Thermal transmittance Uw |
|---|---|
| Existing window | approx. 2.4 W/m²K |
| After upgrading | approx. 0.8 W/m²K |
Annual energy savings
The window renovation results in savings of approximately:
➡️ approx. 166 kWh heating energy per window per year
In addition, the new sealing system reduces uncontrolled air leakage and noticeably improves living comfort.
CO₂ savings per window
Depending on the heating system:
- Gas heating: ≈ 33 kg CO₂ per year
- Oil heating: ≈ 45 kg CO₂ per year
Over a service life of 20 years, this means:
✅ up to 900 kg CO₂ savings per window
CO₂ payback period
Compared to upgrading, a new window saves only approximately:
➡️ approx. 10–15 kg CO₂ more per year
At the same time, manufacturing causes:
- PVC window: up to 300 kg CO₂
- Timber/aluminum window: up to 600 kg CO₂
Renovate windows or install new ones?
New windows may achieve slightly better insulation values, but they cause high CO₂ emissions due to production, transport, and disposal of existing components.
Window upgrading continues to use the existing timber frame and avoids this so-called embodied energy.
Sustainable Window Renovation in the Zurich and St. Gallen Region
The modernization of existing windows is a long-term, practical solution, especially for high-quality timber windows. Our window upgrading combines energy efficiency, RC2 burglary resistance, value preservation, and CO₂ reduction — ideal for residential buildings, multi-family properties, and urban real estate.
Fix Service stands for professional window upgrading, precise workmanship, and sustainable renovation solutions.