The householders were very keen to use a renewable energy system to heat their house. They needed to install a new heating system and were very reluctant to use a fossil fuel system. They attended an information and training day, on wood fuel heating, and decided that it would be possible.

After examining a range of options, they decided that an automatic pellet boiler and fuel hopper could be installed in a small out house adjoining their house.

A 20kW Thermia automatic pellet boiler was chosen to provide sufficient heat and hot water for their part single, part double storey house. Fuel is burnt in a small stoker burner head and ash falls into an ash pan below the grate.

Ash is removed from the ash pan manually at intervals of 3 weeks. The boiler is fully modulating and produces heat when required by the radiator heating system or the hot water needs of the family. At other times the burner remains kindled by additions of small quantities of wood pellets and draught

A wooden fuel hopper, with the capacity to hold up to 4 tonnes of wood pellets, is constructed next to the boiler. Pellets are fed automatically from the base of the V-shaped hopper, through a flexible screw conveyor and into the boiler. The fuel hopper holds up to 3.5 tonnes of wood pellets. A total of 5-6 tonnes perannum are required and is delivered twice per year

Wood pellet fuel is delivered by lorry which parks close to the house and can deliver the wood pellets directly into the storage hopper. This is achieved by a pneumatic system which carries the pellets through a flexible pipe and into the hopper.

A small flue pipe is fitted to carry the flue gases clear of the roof of the outhouse. The cost of the installation was reduced by the householder, who carried out some of the construction work, particularly on the fuel hopper. A 25% capital grant was also obtained from the Bio Energy Capital Grant Scheme. This reduced the cost of the heating system to little more than the cost of the installation of an oil boiler and oil storage tank. Wood fuel pellets are 15% cheaper than the cost of heating oil. The annual heating bill is approximately £650 per annum.