Converting Oil Boilers to Run on Vegetable Oil 


As demand for renewable energy sources grows, people are starting to explore new ways to heat their homes. Especially those with oil boilers due to be phased out over the next decade.  

One option is installing a heat pump, but these pose a host of issues. Not to mention a steep upfront cost. Instead, converting your oil boiler to run on vegetable oil may be the way forward.  

Sound interesting? If you’re looking to upgrade your heating system to a more eco-friendly option without breaking the bank, look no further. Below, we’ll explore the benefits of biofuel boiler conversions, what’s involved and typical costs, to help you make an informed decision.  

Are oil boilers going to be banned in the UK? 

Before we get into the ins and outs of vegetable oil boiler conversions, it’s worth considering why we’re looking for an alternative solution in the first place… 

Of course, most people are well aware of the environmental impact of fossil fuels by now. And many of us are keen to reduce our carbon footprint – from recycling more to using less energy. 

At national level, the government has responded to climate concerns with a Net Zero Strategy. Their aim is to decarbonise all sectors of the UK economy by 2050. In other words, they are taking steps to reduce our greenhouse gas emissions by 100% over the next two decades. 

What are the government proposing? 

One such step is a ban on new oil boilers from 2035 – pushed back from the initial 2026 deadline. After that date, replacement boilers for the country’s 1.7 million oil-heated homes will no longer be available. And homeowners with no mains gas will need to find an alternative.  

The reason for this is that 3-bed oil-heated homes produce an average of 6.5 tonnes of CO₂ annually. To combat this, the government are pushing for more air source heat pumps. But as former Environment Secretary George Eustice and others have highlighted, this option is far from ideal. A heat pump costs around £14,000 and there’s only a £7,500 grant to help fund it.  

And it could cost significantly more if you need to upgrade your insulation, radiators and wiring too. Meanwhile, an oil boiler will usually set you back less than £5,000 – quite a difference! So what happens when kerosene systems are banned and you can’t stretch to a heat pump?

Can I run my oil boiler on vegetable oil?

Thankfully, converting an oil boiler to run on vegetable oil is a much cheaper way to reduce your carbon output. In fact, you could lower your household emissions by nearly 90%!  

And while it isn’t quite as simple as swapping the fuel and hitting go, the process is actually pretty straightforward. Better yet, it typically costs under £500. Let’s take a look in more detail.  

How is vegetable oil used for home heating? 

First things first, you may be wondering how vegetable oil is turned into fuel for heating. Well, when we talk about vegetable oil in this context, we are referring to Hydrotreated Vegetable Oil. Known as HVO, this is synthetic biofuel is made using waste vegetable oil, animal fats, used cooking oil and more. And unlike kerosene, it is considered a zero carbon, non-toxic fuel. 

Additionally, given its comparable chemical structure to heating oil, you can blend HVO with other fuels to lessen their environmental impact. As such, HVO is considered a ‘drop-in fuel’. So as long as you’ve made the updates to your boiler, it can be added in various ratios. This makes HVO far easier to implement than air source heat pumps and their many components. 

You can learn more about Hydrotreated Vegetable Oil (HVO) on the Worcester Bosch website.   

What are the advantages of switching to HVO? 

  • Reduce your household’s CO₂ emissions to just 0.78 tonnes each year – around 88% less than the output of heating oil. What better way to do your bit for the environment? 
  • Update your existing heating system and boiler without funding an entirely new installation. (With a heat pump, you may need larger radiators, new wiring etc). Not only will a conversion save you a lot of money, but it also involves minimal disruption. 
  • Oil systems are a better fit for older properties – particularly those that are difficult to insulate. Luckily, with HVO, you won’t have to sacrifice efficiency in order to go green. 
  • Help your oil boiler run better and for longer – swap to cleaner-burning HVO to extend the life of your current system. 
  • Future-proof your home’s saleability. Want to sell your house in the next decade or so? If it still uses kerosene, you may struggle. Upgrade now to stay ahead of the market. 

What’s involved in converting my oil boiler?  

Converting oil boilers to run on vegetable oil (HVO) isn’t as hard as you might think. And it doesn’t take very long either – it can generally be completed within an hour. But what does conversion process involve and why is it necessary?  

The simple answer is that while HVO shares many of the characteristics of kerosene heating oil, it also has its differences. Namely, vegetable oil burns at a different temperature, therefore the burner and air pressure settings will need alterations. You’ll also need several new components, like a compatible nozzle, oil line and seals – available in handy conversion kits. 

Other than that, everything else will stay the same – you won’t have to upgrade your radiators, for example. You shouldn’t need to buy a new oil tank either, provided it is double-skinned and under twenty years old. In fact, it’s unlikely you’ll even need to clean out your existing tank. As HVO can be safely mixed with heating oil, you can just refill the tank when the level runs low. 

Are there any downsides to making the change? 

The only real disadvantage of converting your boiler right now is the price of fuel. Compared to traditional heating oil, HVO fuel costs roughly 10 to 15% more at the moment. The reason for this is that it’s a relatively new technology and it isn’t quite as readily available just yet.  

With that said, demand for sustainable liquid fuel alternatives is growing. According to Future Ready Fuel, HVO production is set to rise by over 300% in Europe between 2020 and 2025. And as more biodegradable fuel becomes available, prices should level out. There are also plans to introduce blended HVO fuels by 2025 to help make the transition more affordable. 

It’s also worth noting that when used for domestic heating, HVO benefits from a rebated duty rate. So instead of paying the full duty of 52.95p per litre (as you would on diesel), you’ll pay just 10.18p per litre. And there are hopes that this tax could be abolished altogether in future. 

Convert your boiler to run on vegetable oil with Add Heat 

Ready to make the switch to HVO? With over 25 years’ experience under their belts, our Worcester-Bosch accredited heating engineers are on hand to help you upgrade. Whether you live in Macclesfield, Knutsford or somewhere nearby, we’re never far away when you need us.  

Please contact us for a free quote. With Add Heat, converting oil boilers to run on vegetable oil has never been easier.  

Request a call back