Bio-Boilers

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There are several new types of Wood-fuelled heating systems, available. These are also called biomass boilers, they use renewably sourced, wood, pellets or logs to provide the required heat.
The system works by having a boiler which burns the fuel and this heat is used in the central heating system to provide heating and hot water. You could save somewhere in the region of £600 per year compared to paying for electric heating. (Energy Trust 2013)

The benefits

  • This is an affordable heating fuel: The price of wood does vary, throughout the year, but is usually cheaper than using other options to heat your home
  • Bio Boilers get RHI payments. Click here for more information Renewable Heat Premium Payment and the Renewable Heat Incentive.
  • The zero carbon option. Although burning wood does emit carbon dioxide, the carbon dioxide emitted is the same amount that was absorbed whilst the plant was growing. Providing that new trees and plants are grown to replace those that have been burnt, then, the net result is zero. There are some carbon pollution caused by the manufacture and transportation of the fuel, , these are much lower than from other fossil fuels.
  • Costs, savings and earnings

    For boilers, an automatically fed, pellet boiler for an average home cost approximately £11,500 including installation, flue, fuel store and VAT at 5%. If you decide to have a manually fed log boiler systems, the cost would be slightly lower.
    The cost of pellets depends on the size and method of delivery. It does not make sense to buy small quantities. You need to have room for a large fuel store that can take several tons at a time. These are delivered in bulk and will cost approximately £190 per tonne. (Energy Trust 2013
    Logs will cost less than pellets, but costs depend on where you obtain your logs. They cost a lot to transport and will be cheaper if you can purchase more than a years supply and allow them to dry out. The best solution is to have your own log supply from your own property. Search for wood fuel suppliers in your area at the Log Pile website.
    Savings

    The saving depend very much on where you source your fule from and which type of fuel you are replacing. There are also environmental savings to be made in the amount of carbon dioxide emissions these are around 7.5 tonnes a year when a wood-fuelled boiler replaces a solid (coal) fired system or electric storage heating. If you replace a gas heating system with a wood-burning system you could save £100 a year, however, if you replace an electric heating system, you could save as much as £580 per year. (Energy Trust 2013)
    This table shows how much you could save by installing pellet central heating in a typical three-bedroom semi-detached house with basic insulation:
    Fuel replaced Expected saving Expected carbon dioxide saving

    Electricity £630 a year 7.5 tonnes a year
    Oil £270 a year 3.9 tonnes a year
    LPG £790 a year 3.6 tonnes a year
    Coal £270 a year 7.7 tonnes a year
    Gas £90 a year 3.1 tonnes a year
    (Energy Trust 2013)
    These savings assume the your property has been sufficiently insulated,

    Maintenance

    Wood fuelled boilers, need to be swept regularly tro remove the build up of ash from the fuel. These amounts are very low though and usually only need to be done once a week.
    The only other maintenance will be occasional removal of ash and an annual maintenance check (cost c£100). (Energy Trust 2013)
    The chimney must be swept regularly to remove all soot deposits. HETAS recommend that this “should be done at least twice a year, preferably before the heating season to check that the flue has not been blocked by bird’s nests for example and also at the end of the heating season to prevent soot deposits from resting in the chimney during the dormant period”. The Guild of Master Chimney Sweeps recommends that chimneys used in conjunction with wood fuel should be swept quarterly when in use. (Energy Trust 2013)

    Choosing a wood-fuelled heating system

    • Boiler or stove?
    Bio Boilers can replace a standard gas or oil boiler. These can be used to heat radiators for a whole house, and to heat the hot water..
    • Chips, pellets or logs?
    Chips are not suitable for heating a single property, they are used to heat large commercial buildings or groups of properties. Pellets are much more controllable and convenient than logs. Pellet boilers can be operated in much the same manner that gas or oil boilers are. These boilers use automatic fuel feeders. Logs need a lot more work but they can be cheaper than pellets, especially if you have your own supply.
    • Do you have a local fuel supplier?
    There are now suppliers of pellets across the country. Supply of logs is much more locally based and will depend on your area.
    • Do you have space?
    Bio boilers are much larger than their gas or oil equivalents. You will also require storage space to store the fuel. This will also need to be somewhere that can be accessible to delivery trucks but able to supply the boiler.
    • Do you have somewhere to put the flue?
    All Bio Boilers need a have a flue which meets current regulations. This could be an existing chimney but will probably require a new stainless steel lining.
    • Do you need permission?
    All Bio Boilers need to comply with current building regulations. You may not need planning permission, but you should always check.