What is a wood pellet boiler?

There are many types of pellet boilers on the Danish market, but overall, there are two main kinds: compact systems and boilers with a loose stoker. In compact systems, the boiler, storage compartment, and stoker are joined. Automatic pellet loading is possible, the system cleans itself and turns on and off automatically.

With a boiler suitable for wood pellets, a loose stoker can be installed on a boiler, that is as small and compact, such as an oil-fired boiler. Choosing a loose stoker is a cheaper option, especially if an existing boiler is used and constructing the pellet storage compartment is done by yourself. Compact systems are more expensive, but are usually also more efficient and - depending on the system - require little or no work filling pellets, cleaning and emptying ashes.

Why a wood pellet boiler?

Using wood pellets as heat source is both an inexpensive and environmentally friendly way to heat the home/building, and does not require much more work than an oil boiler. But even if burning wood is CO2 neutral, it still emits harmful particles and tar. It is therefore important to choose a system with a good and efficient combustion and to always use clean, dry fuel.

Modern wood pellet boilers are automated regarding regulation, lighting, and they are even self-cleaning. Even filling the pellets can be automated. New boilers have high enough efficiency that there are long intervals between emptying the ashes.

Considerations before purchasing a wood pellet boiler

When purchasing a wood pellet boiler, it is important to consider the location of the boiler and storage of wood pellets. Pellet handling should be easy and the pellets should be kept dry and clean. Moist pellets can block the supply mechanism to the boiler. In addition, impurities such as dust, sand or the like from the surrounding environment can result in unclean combustion.

If there are close neighbours, it's a good idea to ensure that they are not bothered by smoke from the chimney. The municipality has the right to intervene if your smoke is a nuisance to the surroundings and if your pellet stove pollutes too much (according to The Wood Stove Order (Brændeovnsbekendtgørelsen)).

There is more work related to the maintenance and refilling of pellets, and it also requires more storage space for pellets than for instance a heat pump.