Oil Boiler Replacement Cost UK: Fitting, Tanks and Extras

Oil boiler replacement is a several-thousand-pound job once fitting is included. As one current installer example, DMR Heating advertises £5,400 to £7,800 including VAT for typical installations in North Wales and the North West. Your quote can differ substantially, especially if the oil tank, fuel line or boiler location also needs work.

Do not compare that fitted price with a boiler-only listing. The appliance, installation and fuel-storage work are different costs. This guide explains the published price evidence, what can push your quote up, and how to compare a replacement with repairing the existing boiler or changing heating system.

How much does an oil boiler replacement cost?

There is no single fitted price that covers every oil-heated home. A replacement in the existing position can be a different job from moving outdoors or changing the hot-water setup. Start with published benchmarks, then ask an installer to survey the boiler, tank and connections before giving you a complete price.

Worcester Bosch publishes an appliance range of £1,000 to £5,000, with installation of £1,000 to £3,000 stated separately. Its guidance does not itemise the tax treatment or scope of every job. Adding the endpoints gives £2,000 to £8,000, but that is a broad arithmetic envelope, not a survey of typical replacement bills.

DMR Heating’s fitted example is more specific about tax: £5,400 to £7,800 including VAT. The company covers North Wales and the North West and fixes its price after a survey. Treat this as one installer’s published range, not a national average or a quote for your property.

The figures above were checked in September 2026. They are published guidance, not prices from an ExpertSure customer-quote survey. For other fuels and the wider buying process, see our new boiler cost guide.

What makes one replacement more expensive than another?

The biggest differences usually come from the scope of work, rather than the badge on the boiler. Ask whether the existing location and system can be retained. Then check the tank, flue route, controls and pipework. An installer should explain which changes are required and which are optional improvements you can price separately.

Ask for the exact model and output, not just a brand name. Have the installer explain how it matches your heating and hot-water needs. Two quotes for different boiler types, capacities or cylinder arrangements are not like-for-like, even if both say oil boiler replacement at the top.

Keep optional work separate. Replacing a faulty control may be part of getting the system working; choosing a more elaborate controller is a different decision. Our smart thermostat guide can help you form questions, but the installer must confirm compatibility with the proposed oil system.

Will you need a new oil tank as well?

A new boiler does not answer the tank question. Have the existing tank and its installation assessed before accepting the quote. If it is suitable to retain, ask the installer to say so. If replacement is needed, get the reasons and full tank-work scope in writing rather than accepting an unexplained extra allowance.

OFTEC’s domestic oil-storage guidance covers tank condition, structural support, location and secondary containment. Requirements depend on the location and circumstances, so a site assessment matters. The guidance recommends checking the tank during the annual heating service. A tank that still holds oil can have issues that affect replacement work.

Ask how the contractor will deal with the remaining fuel and the old tank. Check whether the price includes a new base, changes to the supply line, removal and disposal. If access crosses a lawn or requires a fence panel to come out, agree who puts everything back afterwards.

Do not assume a cheap tank advertised online is the installed cost. Delivery, lifting, support and connecting it are separate parts of the job. Avoid buying the tank before the installer has confirmed the required type and suitable location. This guide does not give a universal tank allowance because the site work can change the total.

Should you keep the same boiler type?

Keeping the existing arrangement is worth pricing first when it meets your needs. A conversion can solve a real problem, such as freeing indoor space, but it also changes the scope. Ask for separate prices for a suitable replacement and your preferred conversion so you can see what the change costs.

If you want to remove a hot-water cylinder, have the installer assess demand and the proposed combi’s performance. If several people use hot water at once, explain that during the survey. If you want an outdoor boiler, discuss service access and the route back to your heating system as well as the space saved indoors.

Do not select output by copying the label on the old appliance. Ask for an assessment of the home and a written reason for the proposed size. An old boiler may have been selected for a different building condition, extension or hot-water arrangement.

Is repair worth considering before replacement?

Get a diagnosis before treating age alone as a reason to replace the boiler. Compare the cost of the immediate repair, parts availability and the condition of the wider system with a complete replacement quote. Repeated faults can change the decision, but an isolated repair and a failing boiler are different situations.

Ask the engineer to separate the fault from other recommendations. If the burner can be repaired but the tank also needs attention, that tank cost may exist whichever boiler decision you make. Keeping it visible stops the replacement quote from appearing cheaper or more expensive simply because the scopes differ.

Set aside future maintenance in either case. Grant recommends annual servicing for its kerosene oil boilers. Confirm the schedule and guarantee conditions for your chosen model. Our boiler servicing cost guide covers the questions to ask when comparing service prices.

Will a new oil boiler lower your running costs?

A more efficient boiler can use less fuel to provide the same heat, but its purchase price does not tell you the annual saving. Your home’s heat demand, controls, hot-water use and oil price all matter. Ask for the assumptions behind any saving quoted by an installer, including the condition assumed for your existing boiler.

For a purely illustrative comparison, moving from 70% to 90% efficiency would reduce fuel needed for the same useful heat by about 22%. That follows from 1 minus 70 divided by 90. These are assumed efficiencies, not measurements of your boiler or a promised saving. A smaller efficiency improvement gives a smaller fuel reduction.

A payback claim needs a money calculation as well as an efficiency figure. Use your own oil purchase records, consider changes in the household and ask which costs the calculation leaves out. Oil bought in one delivery is not necessarily oil used in that month, so avoid drawing conclusions from a single refill.

Should you compare an oil replacement with a heat pump?

If you have time to choose rather than needing an urgent repair, get a heat-pump assessment alongside the oil quote. Compare the total work each option needs, how it would heat your home and the expected running costs. A cheap appliance price on either side is not enough to make that decision.

Ask the heat-pump installer to assess heat loss, hot-water storage, emitters and electrical requirements. Include any changes in the quote before comparing it with an oil replacement. Our Boiler Upgrade Scheme guide explains funding to investigate; confirm current eligibility before deducting any grant from your budget.

An electric boiler is another option people consider, particularly where space is tight. Its running-cost case needs separate attention. Read our electric boiler cost guide before assuming that a simpler installation will also give you lower bills.

What should a complete oil boiler quote include?

A useful quote identifies the equipment, the work and the boundaries of the price. Request a written scope after the survey and ask for any provisional items to be marked clearly. You should be able to see what could change the total, who approves extra work and what happens before the installer proceeds.

• Exact boiler model, output and indoor or outdoor arrangement.
• Removal of the existing appliance, fitting, flue and agreed pipework.
• Controls, system treatment and any specified accessories.
• Tank assessment and an itemised tank-work price if needed.
• Fuel handling, disposal, access work and making good where relevant.
• Commissioning, handover, guarantee registration and applicable compliance paperwork.
• The total including VAT, payment stages and the treatment of unexpected work.
• Expected installation time and the period without heating or hot water.

Use the OFTEC register to check a technician and the categories of work they cover, including tank work where required. Ask the installer which notification or certification process applies in your part of the UK. Keep the commissioning and guarantee documents with your service records.

Get comparable written quotes before choosing. If one is much cheaper, look for omitted tank work, controls, disposal or tax before assuming it is better value. The useful result is an agreed price for a working heating system, with the uncertain items resolved before installation day.

Laura Bennet

Home Energy & Sustainability Editor

Laura leads coverage on home energy, heating, and sustainable living. With over 12 years in the UK energy sector, she writes about boilers, solar panels, insulation, and eco-friendly upgrades that reduce household costs.

Reviewed by

Tom Reynolds

Business Energy Specialist