How to Price a Boiler Replacement in the UK (2026 Guide)

Boiler replacements look simple on paper. Take the old one off, hang the new one, commission it and leave. In practice the margin on a boiler job is won or lost on the extras you did not spot at survey: a gas pipe that is too small, a condensate with nowhere to go, a flue that has to move, or a system full of sludge. This guide shows how to build up a price for a boiler replacement in the UK in 2026 so you cover every item and still stay competitive.

What customers are paying in 2026

Prices vary by region, brand and how much work sits around the boiler itself. As a rough guide for a typical house, customer prices including VAT sit around these bands:

• Like-for-like combi swap in the same position: £2,200 to £3,500
• Combi swap with a relocation to a new wall or room: £3,000 to £4,500
• System or regular boiler to combi conversion, removing tanks and cylinder: £3,500 to £5,500
• New system boiler with an unvented cylinder: £4,000 to £6,500

London and the South East usually sit at the top of these ranges. Rural jobs with long travel or oil boilers can also come in higher. Treat these as a sense check on your final figure, not as a way to price.

Start with a proper survey

Almost every boiler job that loses money was priced from a phone call. Before you quote, get into the property and check the following:

• Current boiler type, age and location
• Gas supply pipe size from the meter and the run length, since many combis need 22mm to perform
• Incoming mains water pressure and flow rate if you are fitting a combi
• Flue position and clearances to windows, doors, boundaries and eaves
• Where the condensate can discharge, and whether it needs a pump or an external soakaway
• Condition of the system water, radiators and valves
• Existing controls and whether they meet current Building Regulations
• Any signs of asbestos in older airing cupboards, flue sections or boiler casings

Take photos and measurements. They protect you when a customer later asks why the price includes items they did not expect.

Build the price up line by line

1. The boiler and flue

Mid-range combi boilers from the main manufacturers cost roughly £800 to £1,600 at trade price, with larger outputs and premium ranges higher. Add the correct flue kit and any extensions, bends or plume management kits. A standard horizontal flue is around £100 to £250, and vertical or extended flues can double that.

2. System protection

Most manufacturers will not honour an extended warranty without a clean system, an inline magnetic filter and inhibitor. Price a filter at £100 to £180. A chemical flush adds a few hours, and a full powerflush on a dirty system typically adds £300 to £600 to the customer price.

3. Controls

In England, new combi installations must include time and temperature controls plus at least one extra energy saving measure, such as weather compensation, load compensation or a smart thermostat with automation. Allow £100 to £300 for controls depending on what the customer wants. Do not leave this out to win on price, because the installation will not comply.

4. Pipework, gas and condensate

This is where surprises live. Upgrading a gas run from 15mm to 22mm, rerouting pipework to a new boiler position, or fitting a condensate pump all add materials and time. Price each one as its own line so the customer can see what they are paying for and why.

5. Labour

Gas Safe engineer day rates in 2026 typically run from £250 to £400 depending on region. As a guide, allow:

• 1 to 1.5 days for a like-for-like combi swap
• 2 days for a combi relocation
• 2 to 3 days for a conversion that removes tanks and a cylinder

Include time for draining down, commissioning, filling in the Benchmark checklist and showing the customer how to use their controls. These tasks always take longer than people allow.

6. Removal, waste and making good

Allow for removing the old boiler, tanks and cylinder, skip or waste costs, and making good around old flue holes and pipe runs. Be clear in your quote whether redecoration is included, because it usually is not.

Worked example: like-for-like combi swap

• Combi boiler: £1,100
• Horizontal flue kit: £150
• Magnetic filter: £140
• Smart thermostat and controls: £180
• Chemical flush and inhibitor: £150
• Fittings, valves and sundries: £120
• Labour, 1.5 days at £320: £480
• Waste disposal: £50

That gives a cost of £2,370. Add 20% for overheads and profit and the price is £2,844, plus VAT if you are registered. Compare that figure against the 2026 bands above, and if you sit well below the market, check you have not missed something before you lower your margin further.

Compliance you must price in

Gas work must be carried out by a Gas Safe registered engineer. The installation has to be notified under Building Regulations, which your Gas Safe registration handles, and the customer should receive the compliance certificate. Complete the Benchmark checklist and register the manufacturer warranty on the customer's behalf. These steps cost you time, so make sure they are in the price rather than done for free.

Some customers will ask about heat pumps. The Boiler Upgrade Scheme offers a grant towards an air source or ground source heat pump in England and Wales. If you do not install heat pumps yourself, it is worth knowing an installer you can refer the work to.

Present the quote clearly

Customers compare boiler quotes side by side, and the cheapest one often leaves out the filter, the flush or the controls. A clear, itemised quote with a short scope, exclusions and warranty terms helps you win on value instead of price. MyQS helps UK trades build itemised quotes and costings with current UK rates, so every line from the flue kit to the waste skip is in front of the customer before they sign.

FAQ: pricing a boiler replacement

Q: How long does a boiler replacement take?
A: A like-for-like combi swap usually takes one day and sometimes a second morning for commissioning and handover. Relocations take around two days, and a full conversion from a system with tanks and a cylinder can take two to three days.

Q: Should I include a powerflush in every boiler quote?
A: Not always. Test the system water at survey. A clean modern system may only need a chemical flush and inhibitor, while an old system with sludge, cold spots or noisy radiators will need a powerflush to protect the new boiler and the warranty.

Q: Is VAT charged on a boiler replacement?
A: If you are VAT registered, a gas boiler replacement is normally charged at the standard rate of 20%. The reduced rates that apply to some energy saving materials, such as heat pumps, do not cover gas boilers.

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