Biomass boilers qualify for green grants, while electric ones don’t. But are biomass boilers really the secret to green energy? Let’s find out.

We’ve taken a look at how eco-friendly electric boilers are before, but there are other options on the market. Biomass boilers are often proposed as another green source of central heat.

It’d be unfair to say biomass boilers are ‘greenwashed’, they’re definitely an eco-friendlier option than a gas or oil boiler. But they’re not the greenest option on the market, for several reasons.


A modern gas boiler will typically hit an efficiency rate of 90%, which will slowly decrease as the boiler ages. That means that for every 100kWh of energy you put in, you get 90kWh out.

An electric boiler will hit close to 100% with very little drop off.

For a biomass boiler to count as a renewable source of energy, they must hit an 85% efficiency rate. Unfortunately, surveys suggest that they’re only achieving around 76% on average, with many dipping as low as 66.5%.

This is down to numerous factors, including installer competency as well as lowered quality standards. Either way, it’s a major problem with a lot of biomass installs.

Carbon Emissions

That efficiency would be annoying if biomass boilers were a zero-carbon option, but given they do still have a carbon footprint it can really impact how green your heating actually is.

On average, a biomass boiler will produce about 800KG of CO₂ a year (although the exact amount will depend on the size and usage of your boiler).

Now, this is significantly less than a gas boiler creates- but it isn’t zero. It’s very important to keep that in mind.

Theoretically, the carbon produced by the boiler will be equal to the amount absorbed by the fuel during its lifetime. In simple terms, a tree will absorb C0₂ as it grows, then release it when it’s burned. That means the amount of carbon released into the atmosphere is negligible.

However, this doesn’t always work out in practice because…

Sustainable Fuel

Biomass boilers use a renewable fuel source, as they can burn loads of different kinds of wood. You can find reputable sellers out there who carefully manage their forests, and only use waste wood that would decompose anyway. They also make sure to plant trees to replace any they cut down.

This is not the case for all sellers, so it’s very important you find a good source of wood in your local area before committing to biomass. The fuel you’ll see in big shops often isn’t locally sourced,

However, there’s two other problems with seeing biomass as a sustainable fuel source.

Firstly, there’s the ‘carbon payback period’. That means the time it takes for a forest to regrow and reabsorb carbon emissions from biomass boilers might take too long.

Secondly, as the biomass industry grows, more and more fuel is needed. These sustainable sources of fuel simply couldn’t produce the amounts required if biomass were to fully upscale.

With all that said, one nice side benefit of a biomass boiler is that the ash they leave behind makes for an amazing fertiliser, so there’s no harmful waste to worry about.

Compare all this to an electric boiler or heat pump powered by a domestic solar PV set up. That would be 100% sustainable with no stress required.


Biomass fuel costs roughly the same as gas per kWh, but the already mentioned lowered efficiency of many biomass boilers means they can wind up costing you more than gas. It IS significantly cheaper to run a biomass boiler than an electric heat source at time of writing.

However, as mentioned, an electric boiler can be powered by renewable energies, which massively brings the cost down.

Compounding this is the cost to install an electric boiler is significantly lower than a biomass boiler. The average cost of biomass is upwards of £10000, while the average cost of an electric boiler is below £4000. This makes electric boilers far more accessible, and the money you save can be spent on upgrading your insulation or adding solar panels to your home- both of which will make your heating greener.

Final Thoughts

In short? Biomass is a greener option for certain industrial and commercial properties- the sort where low/zero carbon heating might otherwise be impossible. They’re also great for certain domestic properties, again where true no carbon heating simply isn’t an option. But it’s unlikely we’ll see a mass adoption strategy.

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