Capital costs depend on the type and size of system you choose. But installation and commissioning costs tend to be fairly fixed. Stand alone room heaters generally cost around £2,000 - £4,000 installed.
The cost for boilers varies depending on the fuel choice; a typical 20kW (average size required for a three-bedroom semi-detached house) pellet boiler would cost around £5,000 - £14,000 installed, including the cost of the flue and commissioning.
A manual log feed system of the same size would be slightly cheaper. Running costs: Unlike other forms of renewable energy, biomass systems require you to pay for the fuel. Fuel costs generally depend on the distance from your supplier. As a general rule the running costs will be more favourable if you live in an area that doesn't have a gas supply.
This depends on the fuel being replaced and the type of wood fuel being used. It too is more favourable in areas that don't have a gas supply.