Insulation Energy & Cost Savings

Estimate the yearly energy and money saved by upgrading insulation from the change in U-value, area and heating degree-days, free online.

Area to insulate (m²)

Current U-value (W/m²K)

New U-value (W/m²K)

Heating degree-days per year

Heating system efficiency (%)

Energy price per kWh

Cost of the insulation upgrade — optional (optional)

About this calculator

Annual heat loss through a surface = U × A × degree-days × 24 ÷ 1000 (kWh). The saving is the difference between the old and new U-values, divided by the heating system efficiency and multiplied by the energy price. Typical UK/EU heating degree-days are 2000–3000 (base 15.5 °C).