So, how much does it cost to install a new boiler in 2018? We’ve updated this very comprehensive guide to include boiler fitted prices. Along with details on how much it costs to install a combi boiler, we have also added in how much it costs to install a regular boiler and how much it costs to replace a back boiler with a system boiler or a combi boiler.
We’ve also added a new section to our popular guide: How much does a central heating system cost to install? We’ve looked at costs for a 1 and 2 bedroom flat and a 3, 4 and 5 bedroom house.
Boiler installation costs have been broken down in two main parts: (a) the price of the boiler and (b) the price of the boiler and the cost of installing the boiler – i.e. the total price of the installed boiler.
Boiler Installation Costs
Boiler installation costs can be priced according to three job types. They are as follows:
- regular boiler installation – usually a replacement
- combi boiler installation – usually a straight swap
- back boiler replacement – usually an upgrade to a system boiler with a highly efficient hot water cylinder or an upgrade to a combi boiler (NB new conventional gas back boilers are no longer available)
A straight boiler replacement swap (combi boiler for a combi boiler or a system boiler for a system boiler) is usually the most straightforward job. So it is important to note that there could be additional costs involved on top of the costs discussed below.
Additional costs could include:
- if your current gas pipework is undersized it would need to be upgraded
- you’ve upgraded to a combi boiler and now your installation requires a condensate pipe for the first time
- the removal of existing (if now redundant) expansion tanks and water tanks in the loft
- more than the standard building works, e.g. brickwork to fill existing large (old style) flue hole
Cost to Install a Regular Boiler
In the past, a regular boiler would have been the most common boiler found in a domestic property. A regular boiler is the simplest type of boiler and, essentially, is a ‘heat’ only boiler.
This type of boiler will always require a hot water tank and (may) also require a cold water header tank in the loft, depending on whether your system is vented or unvented.
In practice, no two boiler installations are the same so, below, we show two examples where we show estimated costs for (a) replacing a boiler in the same location and (b) replacing and moving the boiler to a new location.
| Install new regular boiler | Approx cost to install boiler | Time to install boiler |
| Replace existing regular boiler with a new boiler – same location | £1,700 | 1 day |
| Replace an existing regular boiler with a new boiler – different location | £2,000 | 2 days |
Cost to Install a Combi Boiler
Combi (or combination) boilers provide heating and also instant hot water via the boiler only. There is is no need for a tank or cylinder to heat the water. Hot water is provided instantaneously on demand. Combi boilers are the most popular type of system in domestic homes in the UK.
When installing a combi boiler it will either be replacing an old existing combi boiler or the new combi boiler is replacing a regular boiler and hot water tank and cylinder.
Replacing an Existing Combi Boiler
Below, we show two examples where we have provided estimated costs for (a) replacing a combi boiler in the same location and (b) replacing and moving the new combi boiler to a new location. The cost of moving the boiler will depend on where it is being moved to.
| Install new combi boiler | Approx cost to install boiler | Time to install boiler |
| Replace existing combi boiler with a new boiler – same location | £1,950 | 1 day |
| Replace an existing combi boiler with a new boiler – different location | £2,250 | 2 days |
Replacing a regular boiler and hot water tank with a combi boiler
There is a lot of work involved when replacing a regular boiler and hot water tank and removing (now redundant) pipework. The is also a need to redirect old and new pipework to the new combi boiler.
A lot of the time the homeowner will want the new combi boiler to be installed in a new location, to free up space for a kitchen extension or loft conversion for example.
Below we have indicated likely costs:
| Convert system/regular boiler to new combi boiler | Approx cost to install boiler | Time to install boiler |
| Replace existing system/regular boiler with a new combi boiler – same location | £2,650 | 2 days |
| Replace existing system/regular boiler with a new combi boiler – different location | £3,000 | 3 days |
Cost to Replace a Back Boiler
Below we have indicated likely costs for replacing a back boiler. We have indicated a cost for (a) removal of the redundant back boiler and replacement with a system boiler whilst retaining the hot water tank and (b) removal of both the redundant back boiler and hot water tank and replacement with a combi boiler.
| Installation of a new boiler | Approx cost to install boiler | Time to install boiler |
| Replace existing back boiler boiler with a new system boiler – keep hot water tank | £2,450 | 2 days |
| Replace existing back boiler and hot water tank with a new combi boiler | £2,650 | 3 days |
Cost of Installing Central Heating
A full central heating system consists of a new boiler plus radiators in all (or most) rooms. Costs can, therefore, vary depending on how large the property is.
The size of the property can vary depending on how many bedrooms you have, how many bathrooms you have and how many extensions and conversions you’ve had done to the property.
Below, we’ve compiled some likely costs for a number of typically sized properties which include a 1 bedroom flat, 2 bedroom flat, 3 bedroom house, 4 bedroom house and a 5 bedroom house. All likely costs include an adequately sized boiler, fitting of a magnetic system filter such as a Magnaclean, a standard flue, all gas and water pipework, thermostatic radiator valves fitted to radiators and all standard manufacturer heating controls.
| Central Heating for | Approx cost | Time to install |
| 1 bedroom flat | £2,450 | 2 days |
| 2 bedroom flat | £2,750 | 3 days |
| 3 bedroom house | £3,200 | 4 days |
| 4 bedroom house | £3,700 | 5 days |
| 5 bedroom house | £4,200 | 5 days |
Boiler Prices
When comparing the price of a new boiler installation you might want to know what the actual boiler costs. Costs can vary widely due to manufacturer build costs and after-sale service and repair guarantees.
Budget boilers are, in our opinion, a false economy. The installation costs always remain fixed regardless of which boiler you choose. That means paying a few extra hundred pounds for a premium make and model could mean fewer breakdowns; with the additional benefit and peace of mind that comes with a longer, better guarantee from a more respected manufacturer.
Budget boilers offer:
- shorter life expectancy: perhaps 8-10 years
- shorter warranties: 1 or 2 years
- not so great customer service
Premium (and some mid-range) boilers offer:
- longer life expectancy: perhaps 10-15 years
- longer warranties: 10-12 years
- better customer service
To sum up, budget boilers will be cheaper to buy but the installation cost will always remain the same. Budget boilers have far less attractive guarantee periods and are harder and more expensive to maintain when they break down.
If you’re considering a replacement boiler then you’ll be presented with wide-ranging information on which manufacturer is best and why. We’ve summed up the reasons for variations in price in our table below.
| Compare | Budget | Premium |
| Cost | £550 | £975 |
| Efficiency | 89% | 98% |
| Guarantee | 1-2 years | 10-12 years |
| Life | 7 years | 12-15 years |
| After Sales Support | OK | Excellent |
| Guarantee | Call out charge | No call out charge |
| Call centre hours | Mon-Fri | Mon-Sat |
| Engineer attending | Subcontractor | Employeed |
*Comparison of a typical 24kW combination boiler.
Related guides:
Compare Combi Boiler Prices – 63 Models Compared!