Guide to New Boiler Installation Costs
Overview of boiler installation costs
HOW TO USE THIS GUIDE
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.
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 inbetween 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. Many of us feel strongly about supporting a local business and we are willing to pay a small premium - over that of a sole trader - to get some intermediate level reassurance from our purchase.
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.
A cautionary note on online quotes without a home visit
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 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 oversized boilers are bad for your bank balance and the planet.
The perils of over sizing boilers
It is very common to oversize boilers 'just in case'. It is in fact extremely inefficient. Oversized boilers 'cycle' excessively - bringing the boiler on and off too much - and accelerate wear and tear. Moreover, as standard TRVs will not reduce the output of the boiler as individual room temperatures are met, so the boiler continues to fire at the same high rate until all the rooms are warm.
To fully understand the implications on efficiency, a quick bit of technical talk is required, but it's very easy! Boilers output at 70 degrees C. In order for the boiler to operating in 'condensing mode' - which is when it is 90% efficient or more - the temperature of the water back to the boiler must be 50 degrees C or lower. In other words, 20 degrees of heat must be dissipated through the radiators as the water goes around. If the boiler is oversized, combined with really any standard or thermostatic TRV, then it will never operate in condensing mode.
Two things can be done to ensure the return temperatures are low enough:
1) 'Range rate' the boiler down to meet your heat requirement. The average heat requirement for a UK home is 6-8kW degrees at peak times. Most fitted boilers are 15kW! It is possible to range rate them down so that they meet your property's needs and check with your engineer that this has been done. To work out the heat requirement of your home the attending engineer should carry out a heat loss survey.
2) Fit Eclipse TRVs by IMI Hydronics. Now we are a fully impartial website and as such products are only actively recommended based on their merits - we receive no sponsorship. The Eclipse TRV is the only TRV currently that will shut down radiators and signal the boiler to reduce its output. Eclipse TRVs will solve overheating in the system and increase efficiencies by up 16%. As a site dedicated to reducing our gas consumption, we highly recommend this product. The cost is on par with standard TRVs.