BIOMASS BOILERS
This renewable solution works in the same way as a conventional boiler, but instead of burning fossil fuel it uses wood to generate warmth. Plant matter in the form of logs, chips or pellets is fed into the appliance’s combustion chamber to create heat to power your home’s heating.
Ideal for homeowners living off the mains gas grid, it’s fairly straightforward to hook a biomass unit up to your property’s existing distribution system, whether that’s radiators or underfloor heating. Because of the high output temperature, this appliance is a good option for larger homes or those that are less well insulated. However, for highly airtight houses, other renewable solutions – such as heat pumps – might be a better fit.
If it’s taken from a sustainably managed source, wood is a carbon neutral fuel. That’s because the CO2 it emits when it burns is less than the amount the tree will have absorbed during its lifetime. Double check for the FSC certification to ensure good sustainability credentials and fuel quality.
There are three specification options for biomass units: pellet, chip-fired or log-fed. The first fuel option is made from compressed wood dust or shavings, with a moisture content of around 8%. It can be automatically fed into the boiler by a hopper, which allows you to manage the output in much the same way you would a conventional appliance. Thanks to the convenience of the pellet model, it’s probably the most common solution for domestic installations. A range of outputs is available, from 10kw to 70kw.
Like pellet boilers, chip-fired versions are fed by an automated hopper. They can be programmed to suit your requirements, too. The storage and feed-in apparatus for this type of unit is typically larger than that of a pellet model, so it’s specified for commercial properties and blocks of flats more often than for single homes.
If you’ve got convenient access to a local source of wood, a log-fed product might be the best solution. Fuel is loaded in by hand, which means the unit needs to be fairly large to accommodate the lengths of wood inside it. As log-burning designs are fed in batches, they burn at a high temperature for short periods of time, with the warmth fed into a buffer tank for later use in space and DHW heating. Because of the significant commitment involved in firing up the boiler, it’s not for everyone.