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Biomass Boilers


Biomass boilers are very similar to conventional gas boilers that you will be familiar with, providing you with space heating and hot water for the entire home, but instead of using gas (or oil) to produce the heat, they combust sustainably sourced wood pellets.


Using wood in place of fossil fuels helps to prevent long-term climate change, since the carbon dioxide released during the combustion was actually absorbed while the tree was growing, so they are essentially carbon neutral.

Each year, approximately 8.5 million tonnes of wood goes into landfill in the UK; this waste wood could be used in either biomass boilers (if converted into the pellets) or burned in wood burning stoves. This would not only provide heat and hot water, but in doing so, it would also ease the pressure on landfill capacity.


How Do Biomass Boilers Work?

Biomass boilers use a process called gasification to produce heat. There is a two stage burn process where the fuel is initially burnt at temperatures of around 600˚C which releases gases. These gases are then re burned which allows the temperature in the burn chamber to reach around 1,200˚C.  The hot gases pass through a metal heat exchanger, which then heats the water on the other side.

On the vast majority of projects thermal stores are used. These are large tanks of water (upwards of 30 litres per kW of boiler output) that act as a heat battery by storing the hot water from the boiler which is then circulated to the central heating system. The biomass boiler has temperature sensors in the thermal store, so it is responsible for keeping it at predefined temperatures. Here the boiler will automatically switch itself on when the thermal store drops below a certain temperature, then when the thermal store is up to temperature it switches itself off to conserve fuel.


Why use biomass instead of fossil fuel?

The integration of a biomass system is relatively simple. In most cases the systems are retro fitted and replace a fossil fuel boiler. The biomass boiler replaces the existing fossil fuel boiler, but the downstream heating system will remain the same, so there is no need to replace the radiators or whatever emitters are in place.

There are three main advantages in switching to biomass:

Fuel savings

Heating with biomass can be a lot cheaper. Where there is an existing wood supply, you can see savings of around 80% against oil after factoring in costs for processing the wood

Using biomass can qualify you for the governments Renewable Heat Incentive

This pays you every quarter for the heat used for 20 years. This not only pays for the initial capex, but provides a healthy return over the lifetime.

Less Emissions

It is considered carbon neutral as releases the same amount of CO₂ when burned as the trees have absorbed during there life. The Biomass Energy Centre sates it can cut emissions by up to 96%


Can biomass boilers be used with radiators or underfloor heating?

Yes. Biomass boilers are capable of heating your whole building and Domestic Hot Water and work extremely well with radiators and underfloor heating.

Can Biomass be used for all of my heating and hot water needs?

If sized correctly, a biomass boiler should take the place of a traditional boiler and is far greener and efficient. The average house uses around 23,000 kWh of heat per year for heating and hot water – a 15kW biomass boiler should be sufficient for a reasonably well insulated home.

Do biomass boilers smell?
Not at all – biomass fuel is burned within a closed, well designed flued system, so should be no smellier or smokier than a standard gas boiler.

Is biomass fuel expensive?

If you have access to free logs, then it won’t cost you a penny to produce hot water or heat your home. If using Pellets it’s significantly cheaper than using oil, LPG or electricity. Fuel prices are always rising, so expect the savings between biomass and fossil fuels. With government’s Renewable Heat Incentive out next year, your system will even pay you.

Can a biomass boiler be connected to my existing heating system?

A Biomass boiler can be seamlessly integrated into your existing heating system. It is no different than replacing your existing Gas or Oil boiler. 

How often do you have to empty the ash?

This depends on whether using Logs or Pellets and what time of the year. With Pellets most people find themselves emptying the ash bin once a fortnight, but your Roses love it.

Do biomass boilers require much maintenance?

Biomass boilers need to be kept clean. You need to make sure you have sufficient fuel in the hopper, check the flue occasionally and empty the ash bin every couple of weeks. But we would recommend any annual maintenance contract with your installation company.

Where can I obtain pellets and store the fuel?

Greenio can help you find a good quality supplier near you.

Can I use a biomass boiler with a solar thermal system?

There are no two technologies that work better together than these two. Solar thermal panels are the most efficient way to generate hot water during the summer months, and in the winter your biomass boiler will take over if your solar thermal panels aren’t generating sufficient heat or hot water.

Do your biomass systems come with a warranty?

All Biomass boilers come with the manufacturers warranty and Greenio's 12 month workmanship Gaurantee 

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Not only is all of the equipment installed by Greenio covered by their manufacturers warranty, all our installations have a 1 year workmanship guarantee as standard


All service and maintenance should be carried out by a HETAS approved contractor. Please check with your contractor before they carry out the work as you will need a certificate for your RHI income.

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