Using a wood-fired boiler

Biofuels include all types of plant material that can be combusted directly or that can be converted into a liquid or gaseous fuel. Biofuels are renewable, unlike fossil fuels (such as oil) which are finite and cannot be recreated. Biofuels include wood fuels – such as fuel wood, pellets, wood chips and briquettes. They can also include peat fuel and biofuel from waste.

Wood is certainly a renewable fuel, but incorrect wood burning can be hazardous to both health and the environment. Wood burners that use old and antiquated boilers release large amounts of pollutants into the air, and flammable tar can form inside the system. Another thing to keep in mind is that an old wood-fired boiler can be very inefficient. The wood is combusted poorly and tar formation is increased. New, effective boilers offer greater efficiency, which can greatly reduce emissions and tar formation. Regardless of whether the boiler is old, the use of an accumulator tank is advantageous. With such a tank, you can fire your wood burner with a high and even load. The accumulator tank acts as an output equaliser that stores heat and then releases it when needed. The wood burning becomes more efficient, more economical and thereby easier on the environment. Today, all new wood-fired boilers that are installed must fulfil the applicable environmental requirements, and an accumulator tank is essentially a must for this.

Get to know your wood-fired boiler

When lighting a cold boiler, it is difficult to completely avoid smoke and emissions of environmentally hazardous substances. This problem can be reduced by getting the fire hot as quickly as possible. A good way to do this is to use a fire-lighting block and plenty of small, dry kindling. A blowtorch will also get the fire going quickly. It will burn at a high temperature and without smoke after just a minute or so.

Be sure to get to know your wood-fired boiler! If you have access to the instruction manual, read it. When using a wood-fired boiler, it should burn intensely and with the right amount of combustion air. Combustion air can be supplied in several places as primary and secondary air. Some boilers have advanced regulation systems that automatically set the combustion air to ensure optimal combustion and minimal emissions.

To keep in mind when burning wood:

• A fireplace damper between the boiler and the chimney can be a good idea. The damper stabilises the air flow and reduces the flue gas temperature in the chimney.
• Install an accumulator tank for safe and convenient wood burning.
• Always use dry wood and never incinerate rubbish in a wood-fired boiler! Chop your wood in the spring so that it has time to dry out. Preferably for a year. Wood that has spent the summer drying provides about 20 percent more energy to the boiler compared to freshly chopped wood.
• Wood burning requires plenty of air. The wood releases flammable gases when it is heated up, and if the gases are to combust, they need sufficient oxygen. Do not allow the fire to smoulder.
• Choose a boiler that fulfils the applicable environmental requirements.
• Contact a master chimney sweep. Wood burning increases fire risks and it is not certain that a chimney built for, say, an oil-fired boiler is suitable for a wood-fired boiler.

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