Calculator
Insulation thickness recommendation
See the recommended external-wall board thickness and the estimated heat-loss reduction for your province and wall build-up.
Recommendation
Recommended thickness4 cmGraphite EPS (λ 0.031) · calculated minimum 3,2 cm
- Current wall U-value
- 1,55 W/m²K
- Zone target (approx.)
- ≤ 0,6 W/m²K
- U after insulation
- 0,52 W/m²K
- Annual heat loss (100 m²)
- 8.927 → 2.976 kWh
- Reduction in wall heat loss
- %67
How is it calculated?
Wall resistance R = Rsi + Σ(d/λ) + Rse (Rsi 0.13; Rse 0.04 m²K/W; incl. 2 cm internal and 3 cm external render). U = 1/R. For your wall R ≈ 0,65 m²K/W.
Required thickness d = λ × (1/U target − R existing), rounded up to the next standard board. Annual loss ≈ U × A × degree-days × 24 / 1000 (kWh).
Indicative only. Zone mapping and target U-values are rounded per the TS 825 approach; thermal bridges, windows and condensation are not included. A licensed engineer's calculation prevails.