By Matthew Knight
Find out which households are most suited to an oil boiler, how oil boilers work and typical oil boiler prices. Once you have all the information you need, why not look at our oil boiler reviews.
For the estimated four million households not connected to the UK's gas network, an oil-powered central heating system with an oil boiler is a key alternative for heating a home.
There are fewer oil boilers to choose from, but the market still offers a good degree of choice when upgrading your oil heating system. We've reviewed and rated more than 80 models on measures including reliability.
Use boiler reviews to filter your results by fuel type, so you can browse the full range of oil boilers we've rated.
Oil boiler prices and costs
The average cost of oil heating for a three-bedroom house is around £1,355. This compares to between £770 and £950 for mains gas, depending on the efficiency of your boiler, and £1,300 for liquid petroleum gas (LPG), the other fuel of choice in the countryside.
Oil boilers can cost anywhere between £1,180 and £2,700, depending on the type and size.
Oil boilers explained
An oil central heating system works in a similar way to a gas-powered system. But instead of using a gas boiler, it uses an oil-fired boiler to heat water. This provides the central heating via radiators and hot water through the taps in your home.
The main difference between the two systems is that you'll need to have your oil supply delivered and stored in a tank. You can read more about heating oil tanks, prices and ordering in our guide to heating oil.
You'll find both heat-only and combination condensing oil boilers on the market. Most oil-fired combination boilers have an internal hot water store to supply domestic hot water, rather than the instantaneous heating more common in gas boilers.
We also found that it’s common for the hot water temperature to decline in oil systems, as more water is used. For more information on the pros and cons of an oil central heating system, see our home heating systems guide.
Oil boiler maintenance and efficiency
Oil is a more efficient fuel than gas, so you'll get a good return on every unit of energy. But, like gas, the price of oil can fluctuate so sometimes it will be more cost effective. Which? members can find local oil suppliers recommended by other members using Which? Local.
To conform with building regulations, since 1 April 2007 oil-fired boilers must have a Sedbuk efficiency of 86% or more (unless an exception is allowed). In practice, only condensing oil-fired boilers can meet this efficiency requirement. Typically, a new condensing oil-fired boiler will have an efficiency of 92% to 93%, compared with 85% for a new non-condensing boiler and 60% to 70% for older systems.
You should choose a professional registered with the Oil Firing Technical Association (Oftec) to install an oil boiler and heating system. Which? Trusted Traders can help you find recommended boiler servicing engineers in your area - and it's advisable to have your oil boiler serviced each year.
Want to know which oil boiler brands are the most reliable? We reveal the best oil boiler brands.