Installing a gas boiler where the house hasn't had one, or rebuilding the heating around a new one, typically costs £2,500 to £6,500. That range covers the boiler, the gas supply, the flue and the controls. It often covers new radiators and pipework too. The spread is wide because no two houses need the same amount of work.
Installation cost by job size
Typical UK gas boiler installation cost, by job size
| Job size | Typical cost | What it usually looks like |
|---|---|---|
| Small | £2,500–£3,500 | One boiler, few or no extra radiators, a short gas run from the meter |
| Typical | £3,500–£5,000 | New radiators and pipework in part of the house, a new flue route |
| Large | £5,000–£6,500+ | Whole-house pipework, a long gas run, a cylinder or difficult floors |
These tiers split the £2,500–£6,500 guide for gas boiler installation. Treat them as a starting point. A written quote after a survey is the only number that counts, and a job with difficult access can go past the top figure.
What changes the price
- Radiator count. Every radiator that has to be supplied or replaced adds pipework, valves and labour.
- Distance from the meter. A long gas run means more pipe, more time and sometimes work below floors or outside.
- The boiler itself. Output, make and whether it comes with a longer warranty all move the figure.
- Hot water. Adding a cylinder, or working around an existing one, changes both the parts and the days on site.
- Access. Lifting floorboards, crossing joists and working in a tight cupboard all cost time.
- Flue route. A flue that can go straight out through a wall is cheaper than one that needs extensions or a vertical run.
What a quote should show
Ask for the quote to be itemised: boiler, flue, pipework, radiators, controls, labour, VAT and anything you've been told is excluded. Two quotes of £3,800 and £4,600 can be for quite different jobs. If one includes a system clean and a filter and the other doesn't, you're not comparing like with like.
Check the engineer is on the Gas Safe Register before you accept anything. You can look anyone up on the Gas Safe Register website, and an installer should show you their ID card without being asked. If the job is only a swap in the same spot, the cheaper gas boiler replacement route is the better fit, and our guide on new gas boiler costs covers it.
A full installation usually runs to two to five days. If a quote promises it all in a single day for a first-time system, ask what has been left out.
Not sure which type of boiler suits the house? Our guide to combi, system and regular boilers explains the difference, and the boiler cost calculator gives a quick range for your own job.
Frequently asked questions
How much does a gas boiler installation cost?
Typically £2,500 to £6,500. A short gas run with few new radiators sits at the low end, and a whole-house job with a long pipe run or a cylinder is at the top.
Does a new gas boiler installation include every radiator?
Not automatically. Some quotes include new radiators and others reuse what's there, so check the written scope before you compare totals.
How long does a gas boiler installation take?
Allow around two to five days. Diagnosis, parts delivery or extra work can stretch that.
Can I swap electric heating for a gas boiler?
Often yes, if the property can have a gas supply. The cost depends on the meter position and the pipework needed, so ask for a survey before you budget.
Ready to talk to a gas boiler installation specialist?
Get Free Quotes →