Guide to New Boiler Installation Costs 2021
How much does a new boiler cost in 2021? Why do prices vary so much?
Updated for 2021. Fitted costs for a new boiler installation are around £1,600 - £3,500 for a combi, £1,400 - £2,500 for heat-only and £1,500 - £2,800 for a system boiler. We provide fully fitted installation cost scenarios below.
Why do fitted prices vary so much these days? We've added some guidance to this popular blog on why fitted prices differ depending on where you shop. For a more tailored cost estimate, try our Boiler Quote Calculator.
- Boiler installation cost scenarios for heat only, combi, system and back boilers
- Basis for our costs guides
- Why do prices vary so much?
- Quotes without a home visit
1) Boiler installation cost scenarios
We provide an estimate of fitted cost based on common scenarios for combi, system, heat-only and back boiler replacements. For example, the cost of a combi to combi or a heat only to a combi or a combi to a system boiler. All of our prices include parts, labour and VAT.
Cost to install a heat only (regular) boiler
Regular boilers are ‘heat only’ boilers. Very simply, the boiler will provide the heating and a cylinder will provide hot water.
The two scenarios below show rough costs for 1) replacing a regular boiler in its existing location and 2) a rough cost for installing a new regular boiler in a new location. The cost of a mid-range heat only boiler in this scenario is £750.
The cost for moving the boiler will vary according to whether it will be in the same room or moved to another room. In both cases we have assumed the cylinder and all other existing equipment are left in place. To review heat only boiler prices by boiler brand read our Guide to Heat Only Boiler Prices
|Installation of a new heat only boiler||Approx. cost with mid range boiler||Time taken|
|1) Replacing an existing heat only boiler with a new boiler, in the same location||£1,800||1 day|
|2) Replacing an existing heat only boiler with a new boiler, in a new location||£2,300||1.5 days|
Cost to install a combi boiler
Combination boilers provide heating and hot water via the boiler (there is no cylinder). There are two main scenarios for combination boilers: A) The new combi boiler is replacing an existing combi boiler or B) the new combi boiler is replacing a regular boiler and hot water cylinder. The cost of a mid-range heat only boiler in this scenario is £900. To know if a combi boiler is suitable for your home, read our Guide to Combi Boilers.
A) Replacing an existing combi boiler
The two cost scenarios below show rough costs for a new combi boiler in the same location and for installing a new combi boiler in a new location. Again the cost for moving the boiler will vary according to where it is moved to.
|Installation of a new combi boiler||Approx. cost with mid range boiler||Time taken|
|1) Replacing an existing combi boiler with a new combi boiler, in the same location||£2,100||1 day|
|2) Replacing an existing combi boiler with a new boiler, in a new location||£2,650||1.5 days|
B) Replacing a regular boiler and hot water cylinder with a combi boiler
In this scenario, there are a lot of additional works to remove the hot water cylinder and re-direct the hot water pipes to the new combi boiler location.
|Conversion to a new combi boiler system||Approx. cost with mid range boiler||Time taken|
|1) Replacing an existing regular boiler and hot water tank with a new combi boiler||£3,250||2.5 days|
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Cost to install a system boiler
System boilers provide heating and work with an unvented hot water tank to provide hot water. System boilers are very high performing and are usually fitted in larger properties with multiple bathrooms.
It is unlikely that someone would wish to swap their existing system boiler and unvented hot water tank for a combi or heat-only boiler, so we have concentrated on common scenarios and provided rough costs for 1) replacing a system boiler in its existing location 2) replacing a heat-only boiler/vented cylinder with a system boiler/unvented hot water tank, 3) replacing a combi with a system boiler/unvented hot water tank (common for those extending their properties). In all cases we have assumed the boiler goes in the same location as the existing boiler. The cost of a mid-range heat only boiler in this scenario is £850. For more on pricing, read our Guide to System Boiler Prices.
|Type of boiler replacement - average figures. Price will vary according to scope of works.||Approx cost with mid range boiler||Time taken|
|1) Replacing a system boiler with a new system boiler and retain the unvented hot water tank||£2,100||1 day|
|2) Replacing a heat-only boiler and hot water cylinder with a system boiler and unvented hot water tank||£5,500||2 days|
|3) Replacing a combi boiler with a system boiler and unvented hot water tank||£5,800||2.5 days|
Cost to replace a back boiler
It is no longer possible to replace a back boiler with another back boiler, read our Guide to Back Boilers to find out more on repairing, maintenance and replacement.
We have provided two approximate costs for replacing a back boiler:
1) The back boiler is removed and replaced with a heat-only boiler, but the hot water tank is retained.
2) The back boiler and hot water tank are removed and replaced with a combination boiler
|Type of boiler replacement - average figures.
Price will vary according to scope of works.
|Approx cost with mid range boiler||Time taken|
|1) Replacing a back boiler with a new heat only boiler and retaining the hot water tank||£2,800||2 days|
|2) Replacing a back boiler and hot water cylinder with a new combi boiler||£3,500||2.5 days|
|3) Replacing existing back boiler with a new style boiler and decorative fireplace||It is currently not possible to install a new back boiler||NA|
2) Basis for our cost guides
We have provided some estimated installation costs for four common scenarios (below).
- 1) Heat Only (regular) boiler installation
- 2) Combination boiler installation
- 3) System boiler installation
- 4) Back boiler replacement
For more on types of boiler (combi, heat-only and system) try our Boiler Types Explained guide.
We have assumed a mid–range boiler cost for a three-bed house with a standard installation set up. Most companies now include a power flush at no extra cost when fitting a new boiler and our prices assume this has been included. To make sure you are getting a genuine, good quality power flush you can read our Guide to Power Flushing. NB there may be additional costs for example if:
- the gas pipe is undersized and needs to be re-run
- the system requires a condensate pipe for the first time
- the system needs to be sealed (i.e. there are currently expansion tanks in the loft)
- there are some building works, for example to brick up a large existing flue hole
For a more detailed breakdown on full central heating costs including radiators, TRVs and controls visit our Guide to Central Heating Costs.
3) Why do fitted boiler prices vary so much?
Why do fitted boiler prices seem to vary so much? To some extent the cost of a boiler installation has always varied depending on who you use, but new operators in the market have changed the landscape again. We guide you on the different operators and changes that affect you.
British Gas and other big companies
At one time, a British Gas boiler installation could cost 50% more than a local sole trader and for often a lessor boiler. Why? Overheads are bigger for one. British Gas has a huge back office of support staff, sales staff and a network of largely employed engineers. It is however precisely because of this facility that British Gas can for many be a reassuring company to use.
All anyone wants is to be able to get support quickly if anything goes wrong and this can be reason enough to pay the extra. That said, the popularity of British Gas boilers remains with older generations, which suggests the model may tail off over time.
At the other end of the spectrum are sole traders. Usually a single engineer, often with an apprentice, working out of their van. Their overheads are lower, which they can pass onto the customer by way of lower labour charges. The downside is getting a return visit fast if something goes wrong.
Small businesses in your area
Offering prices somewhere in-between British Gas and a sole trader, the small local business often has one or two office staff, a few teams of engineers and has invested in systems and procedures.
Online companies with sub contractor networks
Between British Gas, sole trader, local business, it is fairly easy to understand where the price differences are, but they are no longer the only operators. The last three years have seen the emergence of online companies that provide a quote for a new boiler without a home visit. In this setup, each customers' contract is with the online company, but they use a sole trader subcontractor to fit the boiler.
In terms of prices, the online quote companies are able to offer sole trader level prices via a national platform. Firstly because they have dispensed with the need for someone to visit the property and secondly because they can purchase boilers in bulk for bigger discounts. So if you get a price online from such a company, and there are many, you know why they are cheaper despite having a national, British Gas style, presence.
Online quotes from mainstream providers
The popularity of providing quotes online has ballooned over the last 2-3 years with mainstream operators such as British Gas now providing an option to buy a combi boiler online. Even some boiler manufacturers have invested in online quote technology in order to generate work their network of accredited installers. However both still result in a boiler installation without a home visit as the engineer will not have visited the property before the work commences.
4) Quotes without a home visit or video call
Many in the industry have argued that low online quote prices are in fact unsustainable and are designed to harness market share. The models have not been going long enough to know either way. What is important to know is the service you are buying. This is a packaged up sole trader installation, but the engineer will not have seen the job before arriving to fit the boiler.
We still advocate a home visit or a video survey and there is nothing to be lost from engaging with a local sole trader, a small local business and an online quote company to see what each specify and price. The danger of quotes without a home visit is that the system is not properly designed. Too often we find oversized boilers and incompatible controls that do not maximise the efficiencies of the boiler. Such a casual 'one-size-fits-all' approach to boiler installations does nothing to ensure we fit correctly sized boilers onto systems that operate efficiently. For more read our blog: Why our condensing boilers don't condense