Case study

UK Hardwoods

130kW Woodchip boiler

Key facts


September 2012


Space heating for a timber drying shed and kiln for a specialist timber merchant, UK Hardwoods

Boiler and plant

130kW ETA Hack wood chip boiler with a 3,000 litre accumulator tank and 6m diameter agitator and auger system.


The boiler is expected to use approximately 75 tonnes of wood chips per year to produce around 225,000kWh of heat.

Chip storage

Wood is chipped on site and blown directly into the purpose built hopper which holds around 70m³ of chip when full.

Grant / Funding

The project was self-funded and has received Renewable Heat Incentive accreditation.

Savings / Investments

The system burns offcuts from the timber business so fuel costs are restricted to the hire of a contract chipper. Income from the RHI is expected to repay the investment within 6 years.

UK Hardwoods is an established supplier of traditional hardwood flooring, beams and lintels. Dunster was asked to design and install a biomass heating system to heat a storage shed and drying kiln. Dunster worked closely with a controls engineer to integrate the combined temperature and humidity control with the biomass system. Dunster also advised on the design and layout of the plant room and fuel hopper.

Fuel supply and chip handling

Fuel is provided by offcuts and other waste from the timber business which is chipped by a local contractor directly into the fuel store. The fuel store contains enough fuel to require filling only five times  per year. The automatic agitator and auger system transfers the chip from the store into the boiler without the need for any manual intervention.

System design and installation

The system maintains the main storage shed at 25˚C and 50% humidity which is considered ideal air drying conditions for the timber. One corner of the building has been converted into a drying kiln. The temperature within the kiln is gradually raised to 50˚C and maintained at that level for a period of weeks before rising further to over 56˚C for at least 24 hours. This ensures that any insects are killed and allows the timber to reach the optimum moisture content.

The ETA boiler is fully integrated into the control system to ensure maximum efficiency.

UK Hardwoods


Drying time for standard timber is less than half of previous times with a beneficial impact on turnover and stock levels. It has also allowed the effective drying of larger quantities and sizes of timber enabling the business to diversify into new areas.

Download UK Hardwoods case study

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