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A Guide to Biofuel Oil Boilers

If you’re looking for information on boiler prices, our guide on how much a new boiler might cost has you covered.

Over 1.5 million UK homes currently rely on oil boilers to heat their homes. But as the UK edges towards its goal of becoming net-zero by 2050, the government is encouraging anyone with a fossil-fuel-run boiler to look for a greener alternative.

If you have an oil boiler sitting at home, one easy way to drastically reduce your emissions is to transform it into a biofuel boiler. Although it sounds like a long-winded process, it’s actually pretty easy – and cheap too.

Want to learn more? We have everything you need to know about biofuel boilers below – from understanding how they actually work, to costs and carbon emission savings.

Barrels of biofuel

What’s on this page?

What is a biofuel boiler?

Biofuel boilers work in pretty much the same way as a conventional oil boiler, except they run on an eco-friendly substance.

Rather than relying on fossil fuels to heat homes, these boilers use biofuels, which is a type of fuel made from plants, as well as waste cooking oils, vegetable oils, and animal fats.

The most common type of biofuel for home heating is hydrotreated vegetable oil (HVO), which is a synthetic paraffinic diesel – sometimes also called ‘green diesel’.

This type of fuel comes with a plethora of benefits – it has low emissions, is cost effective, and has a storage life of up to 10 years (compared to one year for regular diesel).

If you’re looking for a new boiler, our guide on what a new boiler might cost you has all the information you’ll need on pricing.

Can you convert your current oil boiler into a biofuel one?

Yes, you can convert your oil boiler into a biofuel machine – and why not? You’ll save a tonne of money by not having to install a whole new heating system, which will also help you reduce material waste.

Although converting your oil boiler into a biofuel unit sounds complicated, it’s just a matter of replacing a few key parts. The most important part you’ll need to replace is the burner, since oil and biofuel burn at different temperatures. Doing this will also make sure your biofuel boiler performs at the best possible efficiency.

Biofuel is typically more corrosive than standard heating oil, which means it’s also standard procedure to replace any old seals for biofuel-friendly ones.

How eco friendly are biofuel boilers?

Biofuel boilers are very environmentally friendly – especially when they’re compared to their oil counterpart.

The average UK home using an oil boiler produces 5.3 tonnes of carbon per year, but the UK and Ireland Fuel Distributors Association (UKIFDA) suggests that by swapping to an HVO-powered system, these homeowners can reduce their CO2 emissions by 88%

For context, if all 1.5 million households that currently rely on oil switched to HVO, their collective emissions would drop from 10 million tonnes per year to 1.17 million tonnes.

But how do biofuel emissions compare to other types of fuels? Below, we’ve listed the most common fuels used to heat UK homes, and outlined how many kilograms of CO2e (carbon dioxide equivalent) each one emits per kilowatt hour (kWh).

Fuel typeEmissions kg CO2e per kWh
Oil 0.298
Natural gas0.210
Wood pellets (bulk supply for main heating)0.053
Biofuel (from any biomass source)0.038
Wood logs0.028
Wood chips0.023
Biofuel (from vegetable oil only)0.018

Data from The Government’s Standard Assessment Procedure for Energy Rating of Dwellings

As you can see, biofuel made from vegetable oil (HVO) is much more eco-friendly than other mainstream heating methods.

However, it’s also important to bear in mind that biofuel carbon emissions depend on a number of factors, including its cultivation, harvesting, processing, and how far it’s then transported.

The chart below outlines where the UK currently gets its feedstocks to create biofuel. As you can see, the majority of it comes from other countries – namely China – which suggests that biofuel might not be as eco-friendly as it appears.

Data from Renewable Fuel Statistics Report 2021

Some experts have also questioned how eco-friendly the production process of biofuels is, since it relies on practices that have made agriculture one of the most polluting industries in the world.

Are biofuel oil boilers currently available?

As it stands, the main reason why biofuel is used in the UK is to power green vehicles. In 2021, the UK got through 2,204 million litres of biofuel, which went on transport alone – supplying 5% of total road and non-road mobile machinery fuel for the year.

In terms of domestic biofuel usage, it’s still very early days. After all, the first UK property to transform its oil boiler into a biofuel boiler only made the transition back in 2020.

Although it’s still pretty rare to see biofuel boilers today, UKIFDA launched the next phase of its renewable liquid fuel project in late October 2021, which will look at implementing this type of fuel more widely across UK homes.

someone touching a radiator

How much do biofuel oil boilers cost?

Making an oil boiler suitable for biofuels is not only a simple procedure, but it’s pretty affordable too.

Since most parts in an oil boiler are able to work with different types of fuels, these adaptations typically only cost around £300-600.

The first property in the UK to make the switch from an oil boiler to biofuels was a bungalow in the small village of Scorrier, near Redruth in Cornwall.

Mitchell & Webber, the local fuel distributor, removed the oil from the tank and installed an HVO-compatible nozzle, and carried out some pump pressure adjustments to the boiler. Overall, this process took less than an hour and only cost around £500.

Running costs

New research published by the Oil Firing Technical Association has suggested that all homes using oil heating could swap to 100% liquid biofuels in the future.

During a six-month research project, the organisation also found that introducing a mix of 30% kerosene with 70% fatty acid methyl esters (FAME) could drastically reduce emissions, whilst helping homeowners adjust to the change.

However, the research revealed that 100% biofuel offers the lowest cost and highest impact solution compared to all other options, “costing an average of £166 per tonne of carbon saved, compared to £204 per tonne of carbon saved for a 30% blend of biofuel and kerosene”.

Where does biofuel come from?

Biofuel is made with any carbon source that is easy to replace – usually plants, such as corn stalks, grass, and wood chips.

When biomass is harvested and processed, scientists can break down and convert the plant cells into renewable fuels or chemicals. So, instead of waiting millions of years for nature to change plants into fossil fuels, scientists are trying to speed up this process by making biofuel from plants that are alive today.

The three main sources for making biofuels:

  • Oils from plants – a number of plants naturally produce oil, which can be processed to form biofuel or can be heated directly
  • Sugar crops or starch – these crops can be converted into ethanol through yeast fermentation
  • By-products – wood-gas, ethanol, and methanol can be made from wood chippings and other by-products

Should you get a biofuel boiler?

Research suggests that biofuel boilers will be suitable for any UK homes that currently rely on an oil-run heating system. This way, homeowners only have to make a few adjustments to their oil boilers, costing a few hundred pounds.

If you’re looking for a way to reduce your heating emissions but have found that some options simply take up too much room in your home, biofuel boilers will be a great match for you. These boilers are ideal for smaller properties, since they require much less storage space than other renewable energy heating solutions, such as biomass wood chips or pellets.

If you want to get a biofuel boiler, you’ll also need to make sure your home is well insulated for it to be really effective – otherwise, the heat that’s generated by the biofuel boiler will be lost.

Since most oil-heated properties tend to be older, detached, and often poorly insulated, make sure to factor in how much insulation work will need to be done to your property before installing a biofuel boiler.


Biofuel boilers certainly have a promising future in the UK home-heating scene. Not only can users reduce their carbon footprint by using biofuel, but they also won’t have to worry about forking out a few thousand pounds to make the swap.

Of course, there are a few downsides to biofuel boilers – with some concern over how eco-friendly biofuel actually is. But one thing’s for certain – it’s a huge step up from the carbon-heavy process of burning through kerosene all winter.

Written by:
Beth has been writing about green tech, the environment, and climate change for over three years now – with her work being featured in publications such as The BBC, Forbes, The Express, Greenpeace, and in multiple academic journals. Whether you're after a new set of solar panels, energy-saving tips, or advice on how to reduce your carbon footprint, she's got you covered.
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