How to quote for a boiler replacement

Swapping a boiler is rarely just swapping a boiler. The price depends on whether the customer is staying with the same type, where the new unit goes, the state of the existing system, and what the regulations now require. Quote it without a proper look and you'll hit problems on the day. Here is how to survey the job and build a quote that holds up. This is for Gas Safe registered engineers carrying out the work legally.

Survey before you price

A boiler swap needs eyes on the existing setup. The questions that change the price are all about what's already there and what the customer wants to change.

• Is it a like-for-like swap, or are you changing type, for example a conventional system to a combi?
• Is the boiler staying in the same place, or moving? Moving it means new gas, water and flue runs.
• What's the condition of the existing system, radiators, pipework and cylinder?
• What does the flue route and termination look like under current regulations?
• Is there an existing gas supply of the right size for the new unit's demand?

Account for the regulations

A replacement is the point where older systems often need bringing up to current standards, and that belongs in the quote, not as a surprise on the day. Depending on the system, that can include a system flush or filter, the right flue arrangement, and any required controls. Build in what the job genuinely needs and explain to the customer why it's there. It protects them and it protects your registration.

The line items to include

Break the quote into clear parts so the customer sees what they're paying for and you don't leave anything out.

• The boiler itself and any associated unit (the customer may want a specific make and model).
• Removal and safe disposal of the old boiler and any redundant tank or cylinder.
• Gas, water and condensate pipework, and any flue work.
• System protection: a flush, an inhibitor and a filter where appropriate.
• Controls: thermostat, timer or smart controls if specified.
• Labour for the install and commissioning, plus registering the installation.
• Making good: boxing in, decoration or brickwork around a moved flue, if you're doing it.

Price your own labour and materials

Price the boiler and parts from your suppliers and your labour from the realistic time on site, usually a day or two depending on whether it's a straight swap or a system change. Price your own materials and labour rather than working to someone else's headline figure. A combi conversion with new pipe runs is a very different job from a like-for-like swap, and the quote should reflect that.

Inclusions, exclusions and warranty

Be clear about what's included. If you're not lifting carpets, decorating after a flue move, or upgrading every radiator, say so. State the manufacturer's warranty on the boiler and your own guarantee on the workmanship, including that the warranty depends on annual servicing, so the customer knows the terms from the start.

Present the price cleanly

Put it together as a clear scope, an itemised breakdown, your exclusions, the warranty terms, and the total with VAT shown separately if you're registered. A boiler is a big spend for most households, so a quote that explains itself wins against a one-line text from a rival.

For the standard sections every quote should carry, see what every professional quote should include. If you sometimes can't see the full picture until you start, our guide on quote vs estimate explains when to give a fixed price and when to estimate.