Renewable Heat Incentive Calculator


The calculator is designed to give you an idea of what kind of financial returns you might expect from installing a biomass boiler as opposed to a fossil fuel equivalent. It does not cover everything you need to know to make an investment decision. You need to seek expert advice before undertaking a specific project.

Table 1 Renewable Heat Incentive Tariffs
Boiler Size kW Tier 1 (£/kWh) Tier 2 (£/kWh)
199kW or less £0.0418 £0.0111
200-999kW £0.0518 £0.0224
1000kW or more £0.0203 n/a
Tier 1 cut off to go to Tier 2 is boiler size (kW) multiplied by 1314

Table 2 Energy, CO2 (as net CO2 equivalents CO2e) and bulk density of selected heating fuels
Fuel Traded unit kWh/traded unit kg CO2e emissions/kWh Moisture content Cubic metres per tonne Average boiler efficiency
Heating Oil litre 9.8 0.307     90%
LPG litre 7.07 0.259     90%
Coal (domestic) kg 6.85 0.413     85%
Electricity kWh 1 0.617     100%
Mains gas kWh 1 0.225     90%
Wood Pellets tonne 4680 0.04 10% 1.5 85%
Virgin Woodchip tonne 3490 0.02 30% 5 85%
Recycled Woodchip tonne 4090 0.02 20% 6 85%
Stacked Logs (hardwood) tonne 3490 0.02 30% 2 85%

Boiler Efficiencies - We have used a general estimation for this calculator. Most domestic fossil fuel boiler average efficiencies can be found on the Building Energy Performance Assessment Database
Wood energy and bulk density values - We have used figures from The Biomass Energy Centre. We have used approximations for moisture.
CO2 emissions for fuels - We have used figures from the DEFRA Website