The boiler, flue, filter, thermostat and pipework for a combi boiler swap. A guide from UK builders merchants' public prices, checked on 28 October 2026. Materials only, VAT included. It is not a quote.
What is the home?
| Basic | Mid range | |
|---|---|---|
| Flat, or a 1 or 2 bedroom house | £1,595 to £1,817 | £1,816 to £2,037 |
| 3 bedroom house, one bathroom | £1,726 to £1,902 | £1,901 to £2,077 |
| 4 bedrooms or more, or two bathrooms | £2,220 to £2,353 | £2,352 to £2,484 |
The other answers at their usual setting: 3 bedroom house, one bathroom; Same place as the old boiler; Basic: everyday, plain and practical.
Where the money goes
| The boiler | £1,299 to £1,408 |
| Flue, filter and thermostat | £297 to £341 |
| Pipes, fittings and water treatment | £129 to £154 |
What is included
| Combi boiler 30kW mid range (supply only) 30kW combi suits this size of home | 1 | £1,299 to £1,408 |
| Boiler flue kit horizontal standard | 1 | £101 to £111 |
| Magnetic system filter 22mm | 1 | £97 to £113 |
| Wireless programmable room thermostat | 1 | £97 to £118 |
| Copper pipe 22mm 3m | 2 x length | £52 to £56 |
| Copper pipe 15mm 3m | 1 x length | £13 to £15 |
| Compression fittings assorted 15mm and 22mm | 1 x box | £26 to £38 |
| Isolation valve 15mm | 2 | £2 to £7 |
| Central heating cleaner 500ml Flushing the old system | 1 x bottle | £16 to £21 |
| Central heating inhibitor 500ml Protecting the new one | 1 x bottle | £18 to £19 |
How we worked it out
- a 30kW combi boiler, which suits this size of home.
- A like for like swap in the same place, reusing the pipe runs.
- A combi replacing a system with a hot water cylinder and loft tanks needs more work, not counted here.
- Materials only, VAT included. Fitting must be by a Gas Safe registered engineer. Labour, radiators and taking away the old boiler are not included.
- Basic uses the lower half of each price range.
Get it done
Post the job and up to five ID-checked local traders quote for the whole thing, labour and materials together. Your money is held and released stage by stage, only when you sign each one off.
Questions
How much will a new combi boiler cost?
The materials for a typical new boiler come to about £1,726 to £1,902, VAT included. Labour is on top, and traders quote for it. The figure is a guide from merchants' public prices, not a quote.
Where do the prices come from?
From the public websites of UK merchants such as Screwfix, Toolstation, Wickes, Travis Perkins and Victorian Plumbing, checked on 28 October 2026. Each item has a low and a high price; the basic finish uses the lower half and mid range the upper half.
Does it include labour?
No. These are materials only. Post the job on Mazdurr and up to five ID-checked local traders quote for the whole thing, with your money held until you sign each stage off.