How to Quote a Boiler Replacement - Materials, Labour, and VAT

A boiler replacement is one of the highest-value jobs in a plumber's pipeline - and one of the easiest to underprice. This guide breaks down how to quote a boiler replacement correctly, including materials, labour, VAT at the right rate, and what to exclude so you are protected if the job scope changes.

What goes into a boiler replacement quote?

A boiler replacement quote has four components: the boiler unit, additional materials, labour, and VAT. Each has variables that affect the final price.

1. The boiler unit

Quote the boiler at your trade price plus your materials markup (typically 15-25% on materials). Always specify the exact model and warranty period - this protects you if the customer compares quotes on different units.

Common boiler categories:

• Combi boiler - most common in Ireland and UK domestic market. Provides instant hot water and heating, no cylinder or tank required.
• System boiler - works with a cylinder. Better for homes with multiple bathrooms and high hot water demand.
• Heat-only (regular/conventional) boiler - works with a cylinder and a feed-and-expansion tank in the loft. Common in older properties.

Like-for-like replacements (combi for combi) are faster and cheaper than boiler type conversions. If a customer wants to switch from a regular boiler to a combi, price it as a more complex job - it often involves removing the cylinder and cold water tank, rerouting pipework, and additional labour time.

2. Additional materials

A boiler replacement typically requires materials beyond the boiler unit:

• Flue and flue kit (if not a straight replacement with identical flue position)
• Isolation valves, flexible connections, filter housing
• Magnetic system filter (Magnaclean or equivalent) - worth quoting as an add-on even if not in the original scope
• Inhibitor chemical
• Thermostat and controls (if upgrading from a basic timer to a smart thermostat)
• Pipe fittings and fixings

Quote materials at trade price plus your standard markup. List them as separate line items - this makes the quote transparent and reduces price-comparison pressure.

3. Labour

A standard like-for-like combi boiler replacement takes 4-6 hours for one person, or 3-4 hours with a second person. System flushes, cylinder removals, and complex flue runs add time.

Quote labour as a day rate or as a fixed price per job. Either way, be precise about what that price covers. See how to price a job including materials, labour, markup, and VAT.

4. VAT on boiler replacements

This is where mistakes are made. The VAT rate on boiler work depends on where you are and what exactly you are installing.

VAT rates for boiler replacement by jurisdiction:

In the UK, the 5% rate applies to the supply and installation of a qualifying boiler (a central heating boiler, not a hot water boiler only) in a residential property. The reduction to 5% applies to both parts - supply and fitting. If you are only supplying the boiler and someone else is fitting it, the supply is still 20%; it is the combined supply-and-fix contract that qualifies for 5%.

In Ireland, all plumbing and heating work on residential buildings is subject to 13.5%.

A worked example: combi boiler replacement quote

The following is an example quote structure for a like-for-like combi boiler replacement in a three-bedroom house.

What to exclude from the quote

A clear exclusions list is as important as the quote itself. For a boiler replacement, standard exclusions:

• Power flush (if required by system condition - quote separately)
• Radiator replacement or additional radiators
• Cylinder or tank removal if not already agreed in scope
• Any remedial building work (making good plaster, tiles around the boiler position)
• Asbestos removal if encountered during the job
• Electrical work (if a new spur or fused connection unit is needed for the new controls)
• Gas supply upgrades (if the existing supply is undersized for the new boiler)

Including a clear exclusions list prevents scope creep and protects you if the job turns out to be more complex than expected.

Quote validity and payment terms

Boiler prices fluctuate. State clearly that your quote is valid for 30 days from the date issued. After that, prices may have changed.

For boiler replacements, it is common to take a deposit upfront (often 30-50% of the total, covering the boiler cost) before placing the order. Include your payment terms on the quote.

See our guide on how to write a scope of works for the full scope protection framework.

Tools for quoting boiler jobs

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Or download a free plumber quote template for Ireland to build it manually.