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Best oil boiler brands
A veteran consumer advocate with over two decades of rigorous product-testing experience, Lisa leads our mattress category and joined the home energy team, helping bring clear, actionable advice to consumers.
Every year we ask thousands of boiler owners how satisfied they are with their boiler and whether it's suffered any faults or breakdowns.
Not enough people in either our 2024 or 2025 boiler surveys owned oil boilers for us to score the brands on their feedback. Our survey indicates the number of households with oil boilers has declined in recent years as other methods of heating, such as heat pumps and electric boilers, become more widespread.
However, you can read the results of our 2023 boiler survey of 881 oil boiler owners and 198 boiler engineers below.
Looking for gas boiler reviews? Head to our guide to gas boiler brands rated.
Oil boiler brands rated
From the responses of the 881 owners we asked, we work out which brands have the happiest owners and the lowest fault rates.
But this only makes up part of a boiler brand's overall review. We also ask heating engineers vetted by Which? Trusted Traders what they think of each manufacturer, including how well a brand's boilers are built, how easy they are to fix and service, and how easy it is to get spare parts.
Some engineers are incentivised by brands to recommend their products. We filter out any responses from these engineers, and only use feedback from those with no commercial affiliation with particular brands — so you can be confident our engineer recommendations are unbiased and reliable.
Firebird and Worcester Bosch earned customer scores of five stars and three stars respectively, showing that their owners are very pleased. But do boiler engineers agree with them and how reliable will the boilers prove once installed?
From our May 2023 UK general public online survey of 10,013 people who are responsible for the maintenance of their boiler and our survey of boiler engineers. This included 881 oil boiler owners and 198 Trusted Trader boiler engineers. The Total score for all types of boiler ignores price and is based on: Reliability (40%) How many boilers bought in the past six years developed a fault, factoring in time until first fault and severity. Fault had to be repaired by a trained plumber or engineer. Engineer score (40%) Made up of 15% ease of sourcing parts, 15% ease of replacing common components, 15% ease of servicing, 10% manufacturer support, 20% build quality, 25% unbiased recommendations (barring incentivised engineers). Customer score (20%) How satisfied owners are and likelihood to recommend a brand. Sample size of customers for each brand is in brackets. Best Buy threshold for oil boilers: 78%
Want a gas or electric boiler from a reliable brand? Head to our reviews of the best gas boiler brands and best electric boiler brands.
Firebird oil boiler engineer and reliability scores
Owners rate Firebird oil boilers highly, but do the engineers that install, service and repair them agree? Plus, how likely are they to need a repair?
The Which? boiler survey reveals all you need to know about this popular brand.
Log in or sign up to Which? to see the full results and find which are the best.
Worcester Bosch oil boiler engineer and reliability scores
Owners of Worcester Bosch oil boilers rate them highly, but what do the heating engineers that service them think of how well they're built, how easy they are to repair and how long they last?
Log in or sign up to Which? to see the full results and find which are the best.
Or, if you're looking for a gas boiler, Which? members can find pricing information and our experts' comments in our Worcester Bosch gas boilers review.
The cost of a new boiler will also include system cleaning and labour costs.
Read our guide how much does a new boiler cost? to find out how much you should expect to spend.
Which? Trusted Trader boiler installations
If you're ready to get a new boiler installed, use Which? Trusted Traders to find a reliable boiler installer near you.
For more expert advice, head to our guide to buying the best boiler.
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