Insulation calculator

How it works

Board count is the area divided by board area. Thermal resistance (R) is thickness divided by the material’s conductivity (λ); a higher R means better insulation.

How to measure

Work out the area of the wall or surface, minus windows.

Tips

• Required R-values depend on your climate zone; check the energy code.
• Stagger joints to avoid thermal bridges.
• Some buildings require non-combustible mineral wool.