Oil Boiler Replacement Cost Guide (2026)

Your options when an oil boiler fails

If your oil boiler has failed, replacing it isn’t the only option. A repair is often cheaper.

• Repair: many failed oil boilers have a burner fault, a blocked nozzle or a fuel supply problem that can be fixed. Have it diagnosed before deciding on a replacement.
• Like-for-like replacement: a modern condensing oil boiler from makers such as Grant or Worcester Bosch, in internal, external or kitchen models. This is legal and is what most oil households choose.
• A heat pump: the £9,000 Boiler Upgrade Scheme grant applies to oil-heated homes, but installation typically costs £13,000–£17,000 before the grant.
• HVO: many current oil boilers can be converted to run on HVO renewable fuel with a manufacturer’s kit.

Typical costs in 2026

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

• 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: a yearly service makes breakdowns less likely, and most warranties require it.
• Heat pump alternative: £13,000–£17,000 installed before the £9,000 grant. Your radiators and insulation need to suit one.
• Tank replacement, if needed, is priced separately after a survey by a registered tank installer. We’ll tell you if your tank needs replacing.

What affects the price

• Internal, external or kitchen/utility model (external units have weatherproof casings)
• Heat-only or combi (combi oil boilers cost more and need good mains pressure)
• Flue arrangements and access to the boiler position
• The condition of the fuel line, filter and fire valve, which sometimes need replacing with the boiler
• Whether the system needs a flush or a filter before the new boiler is fitted

Is there an oil boiler ban?

No. The Government’s Warm Homes Plan, published in January 2026, sets no date for phasing out oil boilers, and like-for-like replacement is still legal.