The Short Answer
On our estimates, replacing an oil boiler costs about £2,200 to £4,500 fitted for a regular or system boiler, and £4,000 to £5,500 for an oil combi. We estimate the job takes one to four days.
The price moves with the boiler's output, where it sits (a boiler house or utility room, or the kitchen) and whether the tank or flue needs work too. If the tank is old, I'd price replacing it at the same time.
Oil boiler prices
| Job | Fitted cost |
|---|---|
| Regular or system oil boiler, replaced | £2,200 to £4,500 |
| Oil combi boiler, replaced | £4,000 to £5,500 |
| Replacing the oil tank as well | £1,500 to £4,000 |
What moves the price
On our estimates, a standard boiler-house model sits at the bottom of the range, a kitchen model a few hundred pounds more, a high-output model higher again, and an oil combi at the top. Worcester Bosch, a maker, splits it as the boiler itself plus £1,000 to £3,000 for installation.
Ask each installer to name the model, its output and the warranty, so the quotes compare like for like.
Living with oil
Worcester Bosch says around 4 million UK homes are off the gas grid. An oil boiler needs a storage tank on site, normally in the garden, and Worcester's comparison puts oil as cheaper to run than LPG or electric heating but a little dearer than mains gas. In England, an oil tank within 1.8m of the house, or 760mm of a boundary, needs fire protection, and a tank over 2,500 litres (or near water, a drain or a well) needs a bund. See oil tank rules.
Who can fit it, and the certificate
Fitting an oil boiler is building regulations work. Installers registered with a competent person scheme for oil (APHC, Blue Flame, BESCA, Certsure, NAPIT or OFTEC) can sign the job off themselves, with no building control visit. OFTEC, the oil heating trade body, says self-certified work comes with a workmanship warranty, and that a home can be harder to sell without the compliance certificate (lost ones can be reordered from OFTEC).
In England, building regulations now ask for a carbon monoxide alarm when a new or replacement oil appliance is fitted, as they do for gas and solid fuel.
Grants, and switching to a heat pump
If you get certain benefits and live in private housing, the Energy Company Obligation (ECO) can help pay for replacing or repairing a boiler; owners need an energy rating of D to G, private tenants E to G. Apply through your council or an energy supplier. The current scheme, ECO4, runs until 31 December 2026. See ECO in full.
Oil homes get the biggest heat pump grant. The Boiler Upgrade Scheme takes £7,500 off an air or ground source heat pump, plus an extra £1,500 until March 2027 if the home is heated by oil or LPG and has no mains gas. I'd get a heat pump quote alongside the boiler quotes while that lasts: see air source heat pump costs.
A new oil boiler pays VAT at the standard rate; a heat pump is zero-rated.
Repair or replace?
A well-maintained oil boiler typically lasts 10 to 15 years, and past 20 years it's usually better to replace than repair. That's for a well-maintained boiler, so keep up the yearly service: see boiler servicing.
Get oil boiler quotes
Oil boilers are priced by type, where the boiler sits and the state of the tank.
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Frequently asked questions
How much does it cost to replace an oil boiler?
On our estimates, about £2,200 to £4,500 for a regular or system boiler and £4,000 to £5,500 for an oil combi, fitted.
Should I replace a 20-year-old oil boiler?
Oil boilers typically last 10 to 15 years, and past 20 it's usually better to replace than repair. I'd get quotes before it fails, so you aren't choosing in a rush in winter.
Can I get a free oil boiler?
Possibly, through the Energy Company Obligation if you get certain benefits and the home's energy rating is low. ECO4 runs until 31 December 2026. Apply through your council or an energy supplier.
How long does it take to replace an oil boiler?
About one to four days, on our estimates.
Who can install an oil boiler?
An installer registered with a competent person scheme for oil heating, such as OFTEC, so they can self-certify the work and give you the compliance certificate.
How we priced thisView sources (8, 6 official)
Rules come from the legislation and official guidance, read at source. Prices are our estimates: we check them against trade price data, retailer shelf prices and specialists' price lists, then build them up from their parts so the totals add up. Below are the sources behind the page; the trade price guides we only compare against aren’t listed. Where sources disagreed, we've said so. More on our method.
- IndustryOil boilers, Worcester Bosch. Checked 16 Oct 2026.
- IndustryBuilding regulations and heating installation work, OFTEC. Checked 16 Oct 2026.
- OfficialThe Building Regulations 2010, Schedule 3: self-certification schemes (para 16, roof coverings), legislation.gov.uk. Checked 15 Oct 2026.
- OfficialApproved Document J: Combustion appliances and fuel storage systems (2010 edition incorporating 2010, 2013 and 2022 amendments), GOV.UK. Checked 16 Oct 2026.
- OfficialHelp from your energy supplier: the Energy Company Obligation, GOV.UK. Checked 16 Oct 2026.
- OfficialExtending the ECO4 end date (consultation outcome, updated 23 January 2026), GOV.UK. Checked 16 Oct 2026.
- OfficialApply for the Boiler Upgrade Scheme: what you can get, GOV.UK. Checked 15 Oct 2026.
- OfficialEnergy-saving materials and heating equipment (VAT Notice 708/6), HM Revenue & Customs. Checked 16 Oct 2026.
