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, who is paying, and what exactly you are installing. The rules for Ireland and the UK are different, so they are set out separately below.

Boiler replacement VAT in Ireland and the UK

Ireland: 13.5%, unless the goods pass two-thirds

In Ireland, supplying and fitting a boiler is one supply of construction services at 13.5% - labour and materials together. It is not 13.5% on the labour and 23% on the boiler.

The catch is Revenue's two-thirds rule. If the VAT-exclusive cost to you of the goods used on the job - boiler, flue, filter, fittings - is more than two-thirds of the VAT-exclusive price you charge, the whole job is taxed at 23%. The boiler is the dearest thing on the job, so an expensive boiler on a quick swap can push you over the line. Check it before you send the quote.

Fitting boilers as a subcontractor for a principal contractor under RCT? The reverse charge applies: you do not charge the VAT, your invoice says the principal contractor accounts for it, and RCT is worked out on the VAT-exclusive amount.

UK: 20% for a normal boiler swap

In the UK, a boiler replacement for a customer who pays for it themselves is standard-rated at 20%, labour and materials together. HMRC treats energy-efficient boilers as standard-rated too.

The 5% rate only applies where a grant pays for heating equipment - boilers included - for a qualifying customer, meaning someone aged 60 or over or on certain benefits, and only on the part the grant pays for. Heat pumps and wood-fuelled boilers installed in a home are energy-saving materials and are 0% until 31 March 2027, then 5%.

Subcontracting for a VAT-registered contractor who pays you under CIS? The domestic reverse charge usually applies: your invoice shows the VAT but does not charge it, and the contractor pays it to HMRC.

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. These are example figures only - price your own job from your own supplier prices and rates.

The two-thirds check for Ireland: say the boiler, flue, filter and fittings cost you €1,190 before your markup. Two-thirds of the €2,025 price is €1,350, so the goods are under the line and the job is 13.5%. A dearer boiler, or less labour on the job, can tip it over - and then the whole job is 23%.

What to include and what to exclude

A clear scope is as important as the price. Put both lists on the quote.

Include:

• The exact boiler make, model and output, and the manufacturer warranty period
• Removal and disposal of the old boiler
• Flue, filter, inhibitor and any new controls, itemised
• How the system will be cleaned, if that is in the price
• Commissioning, and the certificates and warranty registration you will hand over

Exclude, and say so in writing:

• Power flush (if required by system condition - quote separately)
• Radiator replacement or additional radiators
• Cylinder or tank removal if not already agreed in scope
• Making good and decorating (plaster, tiles and paint around the old and new boiler positions)
• Asbestos removal if encountered during the job
• Extra work found once the old boiler is off - seized valves, corroded pipework, a sludged system - reported and priced before you carry on
• 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)
• Faults in any parts or controls the customer supplies

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

Get early access - it's free. PayReady AI generates a professional boiler replacement quote from a plain-English job description in under 30 seconds. You set your VAT rate once - 13.5% for most construction work in Ireland, 20% for most work in the UK - and PayReady works it out on every quote and invoice. Free during Early Access. No credit card. Ready in 2 minutes.

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