Oil Boiler Replacement Cost Guide (2026)

Your options when an oil boiler fails

A dead oil boiler in November feels like an emergency, but you usually have more routes than the first quote implies — and the cheapest one is often a repair.

• Repair first — many “dead” oil boilers are a burner fault, a blocked nozzle or a fuel supply problem. Worth a proper diagnosis before anyone talks replacement.
• Like-for-like replacement — a modern condensing oil boiler from the likes of Grant or Worcester Bosch, in internal, external or kitchen models. Entirely legal, and the route most oil households take.
• A heat pump — the £9,000 Boiler Upgrade Scheme grant applies to oil homes, but the installed cost is typically £13,000–£17,000 before the grant, so do the sums for your house rather than the brochure’s.
• HVO-ready — many current oil boilers can later convert to HVO renewable fuel with a manufacturer kit, so a new oil boiler isn’t a dead end.

Typical costs in 2026

Exact pricing depends on the boiler, the flue, access and the state of the tank and fuel line. As honest ballparks:

• Like-for-like oil boiler replacement: typically £2,500–£4,000 installed, with internal heat-only models at the lower end and external or combi models at the upper.
• Annual oil boiler service: local firms typically charge in the £110–£150 range — the cheapest thing on this page, and the one that prevents most of the rest.
• Heat pump alternative: £13,000–£17,000 installed before the £9,000 grant — and the honest comparison includes whether your radiators and insulation suit one.
• Tank replacement, if yours is at end of life, is priced separately at survey — the tank is a registered tank installer’s job and we’ll tell you straight if yours needs one.

What affects the price

• Internal, external or kitchen/utility model — external units carry weatherproof casings
• Heat-only or combi — combi oil boilers cost more and need decent mains pressure
• Flue arrangements and access to the boiler position
• Condition of the fuel line, filter and fire valve — sometimes due replacement with the boiler
• Whether the system needs a flush or a filter before the new boiler goes on it

The oil boiler ban that isn’t

Plenty of oil households have been told they “won’t be allowed” to fit a new oil boiler. It isn’t true. The Government’s Warm Homes Plan, published in January 2026, sets no date for phasing out oil boilers, and like-for-like replacement remains perfectly legal.