Installing a replacement boiler can be a relatively straightforward and hassle free experience, provided you do your research first. It can be very tempting when you’re without heating or hot water to rush into accepting the first quote you receive, without carrying out a few checks into the company beforehand.
We’ll look at all the options to ensure you get the best price from a reputable heating engineer quickly, often the very next day – but first we’ll look at how much a typical boiler replacement will cost.
How much does a new boiler cost?
- Boiler replacement costs range from £2,000 to £4,500, including the price of the boiler itself
- A like-for-like gas boiler installation will cost around £3,000
- A like-for-like oil boiler replacement will cost about £3,500
The cost of installing a replacement boiler varies based on factors like the type of boiler, size, and complexity of the installation. Generally a combi boiler installation of the same type and location will be the fastest and cheapest. Our figures show a combi boiler replacement will cost on average £2,829. If you’re considering installing a new combi you can find everything you need in our best combi boilers guide.
While initial costs may seem significant, the long-term energy savings often justify the investment in a modern efficient boiler.
We’ve summarised these prices in the table below.
| Boiler type | Installed Cost Range | WhatPrice Average* |
|---|---|---|
| Combi Boiler Replacement | £2,000 – £3,500 | £2,829 |
| Conventional Boiler | £2,500 – £4,000 | £3,083 |
| System Boiler | £2,500 – £4,500 | £2,772 |
| Oil Boiler | £2,500 – £5,000 | – |
Finding a heating engineer you can trust
Finding a qualified and reputable heating engineer to assess your property’s heating needs needn’t be too difficult, you just need to understand how the different types of online and offline companies and quotation services work to get the best out of them in the shortest time.
Online boiler replacement companies
Online installers such as Heatable, iHeat & BOXT have become very popular in recent years and for good reason, they offer a fast and efficient way of pricing and arranging a boiler replacement all through their website.
By asking a few very relevant questions about your property and lifestyle they can provide an accurate price online, you can then pick and book an installation date (often as soon as next day) without the hassle of waiting for an engineer to arrive, asses the existing installation and quote – which all takes time.
The downsides of this is exactly that, you never meet anyone from the company before the installation happens. You may be fine with that but sometimes it’s good to meet the installer face-to-face to build a rapport and ensure you’re comfortable with who will be coming into your property before proceeding.
Online companies also generally use subcontractors who are paid a fixed rate to install your boiler, these may be local to you but generally more often than not they won’t be.
The contractors will have been thoroughly vetted beforehand but it’s always best to check they’re Gas Safe Registered beforehand, If it’s an oil boiler then check the Oftec register.
If you’re going to use an online installer for your new boiler then check out their Trustpilot reviews, and read not only the positive reviews but also the negative ones to get a balanced feel for how they’re performing.
We’ve summarised their current ratings across Trustpilot and Google below.
| Installer | Trustpilot rating | Google rating |
|---|---|---|
| Boxt | 4.9/5 | 4.1/5 |
| Heatable | 4.8/5 | 4.9/5 |
| iHeat | 4.9/5 | 4.9/5 |
Boiler price comparison websites
Websites such as Checkatrade, Rated People, Trustatrader & MyBuilder list tradespeople that are subscribed to their service, they all provide some degree of vetting before partnering with them and allow users to provide reviews about their experience using the company. This can be a very useful way of quickly finding boiler installers local to you whilst also reviewing their feedback.
You can call the tradespeople directly but one of the best ways to contact the listed companies is to enter your details on the website, they’ll generally offer a free quotation service which can be handy if you’re busy.
You enter your details which will be reviewed and forwarded to 3 or 4 companies that are looking for work and are willing to pay a small fee for your details, this way the installer will know they’re up against a few other companies for the job and will generally be fast to call you and keenly priced, they’ve paid for the privilege after all.
A couple of things to consider when using these services is that they may be local, regional or even national companies that respond to your job so take this into account when talking to them and the ongoing support they provide, and of course use the advice above about checking their Gas Safe or Oftec qualifications.
Using a service like this won’t cost you a penny, and won’t affect the price you pay as the fee the installers pay is small in comparison to the replacement cost. Only enter your details into one website though, or you’ll be inundated with calls.
Accredited local boiler installers
Professional installation is crucial for safety and compliance with Gas Safe and Building Control regulations and one way to ensure you’re getting the best is to go through the boiler manufacturer’s website and find their accredited installers.
The four biggest manufacturers Worcester, Baxi, Ideal & Vaillant all offer this service via their website which will not only provide details of accredited installers near you but will often also provide you with a longer warranty than if you’d had one of those manufacturer’s boilers installed without using an accredited installer.
It also ensures the engineer is fully trained on the specific boiler in hand and that it’s also integrated with the latest heating controls, ensuring optimal performance and energy efficiency. Once installed, thorough testing and commissioning take place to guarantee the system’s functionality in accordance with the manufacturer’s warranty terms.
Using an accredited installer provides you with a good amount of leverage should the installation not go to plan for whatever reason, the accreditation is a valuable source of work for a lot of companies and will be keen to rectify any issues so as not to jeopardise it.
National energy companies
There’s only one truly nationwide energy company that still offers boiler replacements and that’s British Gas, many of the others now either refer you to one of the online companies or only install heat pumps.
Generally installation timeframes can be longer using British Gas and you’re likely to pay more than you would by using a local installer. On the upside you have the reassurance your installation is backed by a large company with well trained engineers, and the support and service to go alongside that.
One thing to note is that if you’re a British Gas HomeCare customer you don’t have to use British Gas for your boiler installation, you’re free to use whoever you choose.
If you have the time it’s always best to arrange a few quotes, try and find a couple of local businesses and then a regional or national installer to compare against.
Steps to secure the best boiler deal
- Use online installers to get a quick idea of price and fast installation, but be aware they generally use sub-contractors.
- Online installers are great for straightforward boiler replacements, especially combi to combi. Anything more complicated such as a full central heating system installation then it’s best to get a local installer to assess your requirements.
- Use comparison websites to get the best price and quickest access to a few installers, but be mindful they may not be as local as they suggest.
- Try and find an accredited installer for reassurance of a good level of vetting from the manufacturer, product knowledge and longest warranty.
- Use multinational companies for a quote comparison compared to local installers, but they’ll probably be more expensive.
- End of Spring / early Summer is the quietest time for heating engineers and when you’re most likely to get the best price and least disruption as you won’t mind if the heating is off!
- Try to go for a like-for-like boiler swap, it might not always be possible due to boiler model/regulation changes but if you can it’ll be the easiest and quickest install you can find.
User submitted boiler replacement prices
Below you’ll find prices submitted from other WhatPrice users for boiler replacement costs either installed or been quoted, to give you an idea of how much you can expect to pay for a new boiler.
- The average cost submitted to us by WhatPrice users for a gas boiler replacement is £2,926
| Job type | Description | Price | Units | Region | Updated |
|---|---|---|---|---|---|
Gas Boiler Installation | replaced my old gas boiler for a new a rated vaillant condensing gas boiler, the process was painless and the price ok, they renewed all my radiator valves plus all new controls | £2,735 | Total price | West Midlands | 2024 |
Gas Boiler Installation | Worcester Combi Boiler Supply & Installation | £3,160 | Total price | Scotland | 2024 |
Gas Boiler Installation | Move location of boiler from utility to bathroom airing cupboard, new gas and cold water feeds to boiler. Install new Worcester Bosch Combi 28Cdi plus flue/drain. Remove existing boiler,tank/scrap and pipes. New wiring for programmed Drayton thermostat and TRV’s. New cold stop tap and 3 new cold/hot feeds to bathroom and kitchen basins. Left scrap to value £200 | £3,425 | Total price | West Midlands | 2024 |
Gas Boiler Installation | New Vaillant Combi, wireless controls, magnaclean, powerflushing of the heating system, 7 year warranty included. | £2,898 | Total price | South West | 2024 |
Gas Boiler Installation | Remove the existing boiler replaced with A rated boiler condensing combi boiler New boiler would be fitted on where the existing is. power flush the radiators finally the boiler commissioning and notification with Gas Safe labour cost materials & boiler all included on the quote. Potterton titanium boiler. | £2,240 | Total price | London | 2024 |
Gas Boiler Installation | Worcester Bosch 28cdi Greenstar. Magnaclean, full system flush, TRV’s on radiators, Inhibitor, Danfoss wireless controls. | £3,295 | Total price | North East | 2024 |
Gas Boiler Installation | New boiler, flush system, fit a magnaclean and supply 10 year warranty, house heats up in ten minutes, hot water is there in five seconds, we put up with the last combi 9 years. | £2,800 | Total price | West Midlands | 2024 |
Gas Boiler Installation | Replace systems boiler with high efficiency combi boiler Vokera with RF stat & programmer | £1,730 | Total price | Scotland | 2024 |
Gas Boiler Installation | vaillant boiler, with a new fernox filter and wireless room thermostat | £2,475 | Total price | North West | 2024 |
Gas Boiler Installation | Replace standard boiler with new 18kw Worcester bosch condenser boiler, moving location slightly from one wall of corner to the other. Plus 4x thermostatic Radiator valves. Also installed outdoor tap. | £2,500 | Total price | East Midlands | 2024 |
Gas Boiler Installation | Combi boiler removed and another installed in its place. The engineer recommended a Vaillant Eco Tec Plus. We got 7 years warranty as well. 7 radiators powerflushed which took a whole day. | £2,400 | Total price | South East | 2024 |
Gas Boiler Installation | Replace back boiler with new condensing boiler in different position | £4,350 | Total price | North West | 2024 |
Gas Boiler Installation | Boiler replacement, new flue and run a condense pipe, change radiator valve add inhibitor refill system. | £2,633 | Total price | South East | 2024 |
Gas Boiler Installation | replace combi boiler with the same in a newer version | £1,800 | Total price | London | 2024 |
Gas Boiler Installation | Took out old back boiler and replaced it with a Vaillant 28 combi boiler. flushed system and installed a filter | £4,250 | Total price | North East | 2024 |
Gas Boiler Installation | We had a new combination boiler fitted , the previous one had a leaking heat exchanger which also mucked up the electric control board , we had a new Heatline 24kw A rated boiler fitted with a replaced wall thermostat, system was cleaned out with a chemical & some type of magnetic gadget, chemicals were than put in, | £1,800 | Total price | South East | 2024 |
Gas Boiler Installation | supply and fit Worcester 37cdi combi boiler 6 radiators bungalow 5 rooms | £4,230 | Total price | North West | 2024 |
Gas Boiler Installation | had a boiler upgraded, engineer was helpful and gave a lot of info and requirements, highly recommended old unvented cylinder and floor standing boiler removed upgraded with condensing boiler. | £2,700 | Total price | North West | 2024 |
Gas Boiler Installation | Fitted an old combi boiler for a new vaillant one. | £2,050 | Total price | London | 2024 |
Gas Boiler Installation | Replace existing combi boiler with Worcester boiler, fit thermostats to nine rads and fit one new rad. | £4,000 | Total price | South East | 2024 |
Gas Boiler Installation | Replace gas boiler and 19 thermostatic radiator controls and add one new radiator | £3,975 | Total price | South East | 2024 |
Boiler fit only prices
You can buy a boiler from a supplier and then find a heating engineer to fit it for you, this can save you money but be aware if anything goes wrong with the boiler then it can be harder to arrange support from the original installer, not always but it is something to consider. We would advise you find an installer before purchasing the boiler as they generally prefer to supply the boiler themselves. Once you find a willing engineer ensure they are Gas Safe Registered and that they’ll notify Gas Safe of the installation, when this happens Gas Safe will notify your local building control who will issue a Building Regulations Compliance Certificate.
These are example prices from WhatPrice users for heating engineer labour charges to fit a boiler for you. The actual cost will vary with ease of integration into the existing system and the type of fuel required. E.g. a simple replacement of an old combi boiler for a new one with little modification will cost less than if your property has never had a boiler in that location.
- The average cost submitted to us by WhatPrice users for fit only of a gas boiler is £812
| Job type | Description | Price | Units | Region | Updated |
|---|---|---|---|---|---|
Gas Boiler Installation | Changing old convectional boiler to combi. Relocation was into the new loft. ran a new 28mm gas line, powerflush and magnaclean installation, labour only | £1,850 | Labour only | London | 2024 |
Gas Boiler Installation | Old and broken one replaced with new combi boiler. I thought I paid a lot but actually what i paid seems cheap! Very professional, polite and tidy engineer. | £535 | Labour only | East of England | 2024 |
Gas Boiler Installation | Combi swap with all relevant certificates | £735 | Labour only | East Midlands | 2024 |
Gas Boiler Installation | remove old cylinder and tank. install a new combi boiler in the kitchen with wireless thermostat. I provided the boiler. I think is on the high side but I paid as he will do it the next day (took 2 days) | £922 | Labour only | London | 2024 |
Gas Boiler Installation | Change old british gas boiler for new (supplied by myself and change 3 radiators (one new supplied by myself). | £822 | Labour only | East Midlands | 2024 |
Gas Boiler Installation | Like for like combi boiler replacement in same location (supplied by me) Supply and fit magnaclean filter. | £1,100 | Labour only | London | 2024 |
Gas Boiler Installation | I had a conventional boiler replaced with the same conventional boiler but bigger 30KW | £1,300 | Labour only | London | 2024 |
Gas Boiler Installation | Change from gravity fed to combi-system. remove 3 header tanks and all plumbing in loft. new boiler in same location as old. price includes labour, waste disposal and copper. provide cold feed and waste for washing machine. | £1,000 | Labour only | West Midlands | 2024 |
Gas Boiler Installation | REMOVING AND FITTING A NEW MAIN COMBI BOILER | £915 | Labour only | North West | 2024 |
Gas Boiler Installation | Replaced old combi boiler with new condensing combi boiler in same location in kitchen (easy access). Included new flue kit of course, but core supply of gas, water and electricity were already there as it was a replacement. | £490 | Labour only | London | 2024 |
Gas Boiler Installation | Remove old combi boiler and replace with condensing vaillant combi. | £600 | Labour only | North West | 2024 |
Gas Boiler Installation | change vaillant combi to combi, and run 22m gas pipe from meter, power flush system | £560 | Labour only | London | 2024 |
Gas Boiler Installation | Take out old combi boiler. Fit new combi boiler. drain down system and test. 4 Bed house, 12 Radiators. All done within 6 hours. | £450 | Labour only | East Midlands | 2024 |
Gas Boiler Installation | the price is for replacing an existing combination boiler with a landlords safety certificate. | £590 | Labour only | London | 2024 |
Gas Boiler Installation | Replace old heat only boiler with new Vaillant Eco tech heat only boiler. Flue and associated pipe work | £515 | Labour only | London | 2024 |
Gas Boiler Installation | Remove old non condensing combi and ft Glow Worm condensing combi. Condensate drain added, system flushed and protector added. All work carried out and notified by Gas Safe Engineer. | £600 | Labour only | London | 2024 |
Potential new boiler cost savings
Replacing your old boiler with a newer more efficient model can help reduce your energy bills. Estimated annual savings are as follows.
| Type of property | Your old boiler efficiency rating & potential saving | |||
| D | E | F | G | |
| (78-82%) | (74-78%) | (70-74%) | (<70%) | |
| Bungalow (detached) | £150 | £160 | £180 | £260 |
| Detached house | £190 | £240 | £300 | £430 |
| Flat (mid floor) | £60 | £65 | £75 | £110 |
| Semi-detached house | £160 | £180 | £200 | £280 |
| Mid-terrace house | £130 | £150 | £170 | £240 |
FAQs
How much will a combi boiler replacement cost?
A combi boiler swap is the cheapest and fastest boiler to install, according to our figures you can expect to pay around £2,829 for a combi replacement.
Are there any financing options available for a new boiler?
Yes, many suppliers offer financing options such as 0% interest-free credit, pay monthly plans, or buy now, pay later schemes. Check with your installer for available offers.
How long does it take to replace a boiler?
A straightforward boiler swap can generally be done in 1-2 days, if any other system changes are required such as new pipework, radiators or a new tank then anything from 2-5 days is reasonable.
What warranties are available?
Most new boilers come with a warranty of 5 to 12 years, covering parts and labour. The longest warranties are generally found by using an engineer accredited by the manufacturer. Ensure your boiler is serviced annually to keep the warranty valid.
What is a Conventional Boiler? (also known as a Regular, Heat Only or Open Vented boiler)
A conventional boiler heats water that is stored in a hot water cylinder. The tank is often placed in an airing cupboard usually off the landing. There is also a cold water storage and an expansion cistern in the loft. The advantage of this is that a large volume of water (at a reasonable pressure head) is available, the disadvantage is that the hot water is not available on demand. Heating up the large volume of water in the tank has a cost disadvantage if only a small amount is needed (a combi boiler is better in this case), but the systems are relatively cheap to maintain and good for larger homes that have high hot water demand. Many older systems that are in need of replacing are conventional boilers.
What is a Combi Boiler? (also known as a Combination Boiler)
A combi boiler differs in that the water is not stored in a tank anywhere (cold or hot), but rather supplied on demand when you need it. The term combination comes from the fact that it provides hot water for washing and hot water for heating.
The advantages are that they save space (no pipework or tanks in the loft) and hence are easier to install (for a professional). Also, by heating only the water you want you can save money and be more environmentally friendly. The disadvantage is that the flow rate from the boiler can be slower depending on mains pressure and boiler size. A more powerful combi boiler could provide hot water at mains pressure and also sustain a decent flow rate through more than one tap at a time again depending on mains pressure.
It used to be the case that combi boilers were better suited to smaller houses (where the likelihood of more than one tap being used was reduced). However, there are new types of combi that have a small storage tank that means that can cope with a higher flow rate.
What is a Condensing Boiler?
A condensing boiler uses advanced technology to maximize the efficiency of the heat it produces. When burning fuels like gas or oil, gases are released through a flue. In a traditional non-condensing boiler, these gases are released into the air, and their heat potential is wasted.
In contrast, a condensing boiler captures and reuses the hot gases by directing them through a heat exchanger into what’s called the primary circuit. Depending on the type of boiler, this primary circuit then distributes the heat to either the heating system (radiators) or the hot water supply. In a combination boiler, the hot water is usually heated through a secondary heat exchanger known as a plate-to-plate system. In a heat-only setup, the domestic hot water is heated and stored in a cylinder within the property.
What size of boiler do I need?
The required heat output of your boiler is determined by the total requirement of all your radiators and your hot water needs. Allowance needs to taken for the heat loss through the walls, floor, windows and roof of your house. Therefore, if a property has undergone a serious insulation makeover (cavity walls, double glazing, draft reduction, loft insulation) you may find your need a smaller boiler capacity. The specific calculation/estimation will be done by your plumber.