Questions & Answers on Biomass Heating
Q&A about biomass heating & wood fuelled heating.
Is Green Systems UK a HETAS registered company?
Green Systems UK is a HETAS registered company (company registration number 1845) and is accredited for the installation of solid fuel appliances and hot water systems, installation of dry appliances, service and maintenance of appliances, installation of twin walled flexible flue liners, installation of mechanically fed (wood log, chip, pellet) appliances and flues.
Burning wood isn't renewable energy is it?!
 Wood fuel or biomass is a renewable energy source. When burnt the carbon dioxide (CO2) that is released into the atmosphere is only the CO2 that the plant would release when it died and decomposed. If you purchase fuel from a sustainable source you will not increase the carbon dioxide levels in the atmosphere. Wood is stored solar energy.
Can I use wood fuel to heat radiators and underfloor heating?
Wood fuel is one of the best renewable energy technologies for heating. Modern highly efficient boilers and stoves are capable of heating your whole building and work very well with radiators and underfloor heating. You have a choice of fuel including logs, wood pellets, wood chips and grain.
Do the boilers smoke or smell?
Generally no they don't. If you see 'smoke' coming out of the flue it's more likely to be water vapour when the boiler is initially fired up, once burning properly the boilers exhaust gases are clear. The smell you get around the boiler is sweet and woody as you might expect. If the door to the boiler is opened the smoke is sucked back into the boiler so none escapes to the room. It does smell smokey but it's not an offensive smell, it's quite homely actually.
How often do I have to fill up a domestic wood pellet boiler?
If you have a hopper connected to the boiler you will have to fill this weekly by hand. Usually this is done by emptying the delivered 15kg sacks of pellets into the hopper. If you have a silo connected to the boiler this will be filled by bulk truck delivery (typical deliveries are three to five tonnes). The boiler will draw pellets from the silo and feed itself as required.
How often do I have to fill up a log boiler?
Once daily filling is usually required and this would be done by hand.
Can I burn wood pellets in a smokeless zone?
The Froling range of biomass boilers are included on the exempt appliances list so yes they can be installed in the smokeless zone.
Do pellet boilers make a noise?
You do get a noise from the auger that feeds the combustion chamber with pellets from the hopper. This sounds like a quiet mechanical whirr about every thirty seconds that lasts for about half a second. It might get on your nerves if it could be heard in a lounge area but you would become accustomed to it, like how you would get used to a ticking clock. The noise of combustion is a low hum very similar to an oil fired boiler.
Where can I buy wood pellets and how much do they cost?
Please visit the website of the Farnham, Surrey based company Harvest Wood Fuels at http://www.harvestwoodfuels.co.uk for wood pellet fuel deliveries.
Current prices for wood pellets are £200 per tonne + VAT@5% & delivery for blown loose deliveries and £210 per tonne + VAT@5% & delivery for pre bagged sacks on a pallet.
What's the maximum distance from truck to silo for blown pellet deliveries?
A maximum of 30m for deliveries but recommended only up to 15m.
What's the maximum distance from the silo to the boiler?
The maximum distance from the silo to the boiler is 15m. The boiler and silo do not have to be in the same building.
How much will a domestic biomass boiler installation cost?
For a supply and full installation of a basic pellet boiler prices in the region of £6,500 should be expected. For the high spec pellet boiler models with weather compensation you will be looking at £12,500 for a full installation. For supply and installation of a basic log burning boiler and accumulator tank/s prices start at around £7,000. For high spec log burning boilers with Lambda oxygen control and weather compensation you should expect £12,500.
Is there a feed in tariff for Biomass Boilers?
Yes there is it's called the RHI and the payback is as follows;
Biomass boilers up to 45kW will get an annual grant of 9p/kWh for 15 years.
Biomass boilers from 45kW to 500kW will get an annual grant of 6.5p/kWh for 15 years.
Are your wood burning boilers condensing boilers?
They are not condensing but they are over 90% efficient making them as good as condensing boilers. You can't buy wood fuelled condensing boilers.
How do Wood Chips compare to heating oil?
Wood Chips consist of wood that has been mechanically chopped to a suitably small size, fine wood chips must be used. We recommend a chip size of 5 to 30mm with a moisture content a 25% or less.*15m3 of coniferous soft wood or 11m3 of decidous or hard wood can substitute approximately 1000 litres of heating oil.
How do Wood Pellets compare to heating oil?
Wood pellets are produced as by-products from the wood industry, e.g. from chips and sawdust whaich are compressed into pellets. *2.2 kilogrames of wood pellets can substitute approxiamtely 1 litre of heating oil
Please note: *The calorific values indicated are for guidance only since the comparison is dependant on several conditions, such as the composition and water contents of the bio-fuel.
I want to produce my own wood chips and use them as fuel, can I do this?
This is possible but you need to get the wood chip size and moisture content correct. Just because a wood chip boiler burns wood chips it doesn't mean it will burn any wood chip. An oil boiler burns oil but you wouldn't fill it full of cooking oil would you? The fuel has to be fit for purpose. The G30 Woodchip Specification is the grade of fuel used in our range of wood chip boilers and most other small scale wood chip boilers. The sizing is as follows for the look, size and content of the processed chips, 4% under 1mm, 20% 1 to 3mm, 60% to 100% 3 to 16mm and 20% over 16mm. The maximum extremes of the odd wood chip are area 30mm2 and length 85mm. With a W35 moisture content of 30% to 34%. The processed wood chip should also contain a low bark content, preferably with the wood being stripped of bark prior to chipping.
How many tonnes of pellets would I need to heat my home?
Heat Load of Home kW----------Consumption of Pellets kg-----------Size of Annual Store m3
_________10______________________4,000______________________9.0___________
_________15______________________6,000_____________________13.5___________
_________20______________________8,000_____________________18.0___________
_________25_____________________10,000_____________________22.5___________
_________30_____________________12,000_____________________27.0___________
A wood pellet boiler size for your project will come up smaller than a traditional gas or oil boiler because these fossil fuelled boilers were always over sized. When sizing for renewables it is best to size the boiler spot on the heatload. So a 25kW gas/oil boiler will not mean a 25kW pellet boiler, usually a 15kW pellet boiler is more than adequate to heat a reasonably well insulated three to four bedroomed home. The figures on pellet consumption are just for guidance.
Could I be self sufficient in wood?
You would need to have sufficient land to produce 6 to 12 tonnes dry logs p.a. This could be done by planting a hectare of poplar which after the third year would produce approximately 10 tonnes of logs pa.
How does a wood heating system compare to using traditional fossil fuels?
Mains gas is still the cheapest way to heat if it's already in your area. But, as a general guide wood pellets, woodchips and logs are usually a cheaper way to heat than electricity, LPG and sometimes oil.
How do I know what size boiler I will need?
You will be asked details of floor area m2 you wish to heat when you enquire about an installation. As a rule of thumb you can estimate 75W/m2 for well insulated buildings and 50W/m2 for new builds.
How do I know what size accumulator tank I will need?
Stored energy is calculated by multiplying the tank volume by the delta T in deg C (difference between stored temperature and temperature that tank is cooled to) and multiplying by 1.16 to give Wh. Divide by 1000 to get kWh.
Should I run the Biomass Boiler in the summer for hot water heating?
We recommend solar thermal heating for hot water in the warmer months. A well sized solar water heating system will heat all of your hot water from when the heating season finishes to when it starts again. So you may shut down the boiler from April/May to September/October and let the solar take over.
We have an out-buildings can we use these to house the boiler?
Out-buildings as long as they are water tight are a good choice for the biomass boiler, accumulator tank (if needed) and the hopper or silo. There is usually a lot of equipment installed on a project and it's a reasonable size, much larger than a traditional gas or oil boiler.
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