Wood pellet heating for space heating and hot water

1What are pellets made from?
Wood pellets are usually made of highly compressed sawdust, a by-product of the wood processing industry.

Pellets manufactured for industrial purposes (as co-firing in a coal-fired power plant) can also be made from materials such as recycled wood and straw.

No chemical additives are needed for pellets made from sawdust as the natural lignin in the wood acts as a binder.
2What are the current wood pellet fuel standards and quality
Using the right quality pellets for your pellet stove or boiler is vitally important. Poor quality pellets are likely to crumble and produce fines, blocking the feed mechanism.

They might also contain traces of foreign materials that will damage your heating equipment. Failing to use the right quality fuel could also damage irreversibly your boiler and invalidate the manufacturer’s or installer’s warranty.

Wood chip and log heating for space heating and hot water

1Could I be self-sufficient in providing logs for my boiler?
You would need to have sufficient land to produce 6 to 12 tonnes dry logs per annum. This could be done by planting a hectare of poplar which, after the third year, would produce approximately 10 tonnes of logs each year.
2How does the running cost of using a wood heating system compare to using a fossil fuel?
It's always difficult to make comparisons between the cost of heating with different fuels, given that there are a number of different suppliers in the market, different electricity tariffs for day and night time and different costs according to the quantity of wood purchased and its delivery distance (particularly for solid fuels such as logs and coal).

In today's market woodchip, wood pellets and logs are generally a cheaper way of heating than electricity, heating oil or LPG. In some instances, they could be cheaper than natural gas.
3What size boiler/stove do I need?
Heating output is specified in kilowatts, kW, (metric units) or BTUs (Imperial units) and represents the rate at which the system can deliver heat energy.

Sizing of heating systems should be done by a qualified heating engineer. It's dependent on many factors including levels of insulation and draught proofing of the building, the lowest outside temperature for your locality and patterns of use. However, the following 'rule of thumb' can be useful for making initial sizing estimates for central heating boilers:

Boiler size (in kW) = volume to be heated (in cubic metres) divided by 34 (for a reasonably well-insulated house) (source: National Energy Foundation).

It's important to bear in mind that all biomass boilers burn most cleanly and efficiently when working at their maximum output. Therefore, it's best not to over-specify but to choose a biomass boiler which is sized to meet your average heating requirements with additional heating sources to provide extra heat on the coldest days.


1What are the emissions from burning wood?
According to National Energy Statistics the main emissions from burning clean, seasoned wood will consist largely of water vapor and carbon dioxide (plus nitrogen and oxygen from the combustion air). The emissions will also contain traces of carbon monoxide, particulates, and volatile organic compounds.

These emissions are also produced when fossil fuels like gas and oil are burned to produce energy. However, this is not a reason to be complacent. Instead, it highlights the need to consider seriously the appliance that the wood is burned in and the quality of the wood fuel that is used.

This is why we at Enerxcel thrive to find the most carbon neutral state of the art wood burning appliances whilst maintaining the low cost of the installation.
2Can I burn wood in a smokeless zone?
Wood can be burned in a smokeless zone if the appliance (stove or boiler) has an Exemption Certificate. Companies which manufacture log stoves with Exemption Certificates include Clearview, Vermont Castings, Dovre, Dunsley Yorkshire Stoves, Morso and Jotul.

There are also a number of pellet stoves and boilers that have Exemption Certificates. These include boilers and stoves manufactured by the likes of Binder, Biotech, Extraflame, Fröling, Giles, Guntamatic, Hargassner, KWB and Solarfocus.
3What is RHI:
The Renewable Heat Incentive (RHI) is a UK Government scheme set up to encourage the installation of renewable heat technologies amongst householders, communities, and businesses through financial incentives.

It is the first of its kind in the world and the UK Government expects the RHI to contribute towards the 2020 ambition of 12% of heating coming from renewable sources.
4Who is eligible?
From homeowners to SME’s, medium & large scale businesses and farmers. The RHI runs for both domestic and non-domestic installations to provide financial support over the eligible period (see current tariff). The scheme covers England, Wales and Scotland and should support the replacement of fossil fuel energy appliances such as Electric, Oil and LPG boilers.

Since the RHI has been launched in November 2011, it is the main economic driver affecting the integration of renewables for space heating and hot water.