How much does a new boiler cost?

Maybe it has come to the point where your old boiler has packed up, and the part you need is no longer available. Or perhaps you are pre-empting all those problems by changing your boiler before it gives up the ghost. Either way, knowing how much you should expect to pay for a new boiler is a bit tricky.

Why does one person get a new boiler for under £2,000 and another for £4,000? In this blog, we want to give you an idea of some of the costs involved, and what makes some jobs more expensive than others.

The boiler

Determining the cost of a boiler install is unfortunately not a simple business; it depends on a variety of different things. Firstly it depends on the size of the boiler you are installing – a small flat for example will require a much smaller boiler than a large house and the unit itself will be a few hundred pounds cheaper than a larger model of boiler.

>>> Can I get a grant for a free boiler? <<<

In addition it depends on what type of boiler you had originally and what type of boiler you are swapping to. On the whole there are two types of boiler – a regular boiler (with the hot water tank) and a combi boiler that makes hot water on demand (without a hot water tank). Approximate starting prices are discussed below:

    • If you are keeping the same type of boiler (e.g. if you have a existing combi boiler you are replacing it with a new combi), the price to buy and install it will start at about £1300 provided there are no real plumbing adjustments required. As a guide, the price of installing a new boiler is approximately £600 – £1000 and then you will need to pay for the boiler on top of that.
    • If you want to swap a regular boiler with a combi boiler unfortunately there will be a lot of pipework changes needed (although you will be doing away with your hot water tank!), so the price to buy and fit this type of boiler starts at about £1800.

All the prices listed above are starting prices – the final prices will be impacted by all the factors discussed below.

Gas pressure

Your heating engineer should always check the gas pressure going in to the boiler, because if this is insufficient, it could cause you problems. One of the issues that often comes up is where too narrow a pipe is used to take the gas from the mains at the meter to the boiler (usually to cut costs). If you have a narrow pipe coming out of your meter (15mm or less) you could have an extra cost on your hands.

Moving a boiler

Unfortunately, there are occasions when moving the position of the boiler will be necessary. If you have an old floor-mounted boiler, a back boiler, or simply a boiler in an unsuitable position (ideally boilers are now situated on external walls) the job will require significant rerouting of pipework and the further you have to move it, the more expensive the job.

Building regulations and flues

Over the years, legislation has changed dramatically, meaning a boiler installation 30 years ago will likely not meet current standards. If your flue is dispersing waste gas into a street for example, you may need a plume diverter to ensure people aren’t affected by the emissions. If your boiler is mounted in the centre of the house with the flue going up the chimney, this will no longer meet the regulations, and as such the boiler will need a new position on an external facing wall.

>>> What is the best brand of boiler to install? <<<

So you want your new boiler in exactly the same place – chances are you will be swapping an old conventional boiler with no condense pipe for a new condensing model, and as such, a condense pipe will need to run to a downpipe, sink or gutter. The difficulty involved here will also add to the cost of the job. You may even have an old asbestos flue, in which case you will need a specialist in to remove the material before the boiler can be installed.

Radiators and heating controls

Adding or replacing radiators and tanks will obviously make the job more expensive. Fortunately, it is not normally necessary to change them, and it is really easy to remove an old tank if you are switching to a combi. We would always recommend getting heating controls – which includes as a minimum a programmer and thermostat, but we would also suggest thermostatic valves on the radiators (known as TRVs) where the property is larger.

>>> British Gas – an Expensive way to get a new boiler! <<<

As an approximate guide, a programmer and thermostat will cost you a couple of hundred pounds, and each TRV for each radiator will cost about £50. If you have an outdated programmer or thermostat, or are lacking thermostatic radiator valves, it is really worth getting these replaced. They tend to pay back fairly quickly and don’t cost a lot of money.

Price varies dramatically with installer!

It is worth mentioning that although the workmanship of different installers does vary, as a bare minimum we recommend your choosen installer is Gas Safe – A Gas Safe registered engineer has been checked to make sure they are competent and qualified to work safely and legally with gas. This is the recognised installer mark of quality and has replaced the old ‘Corgi Registered’ mark.


We too have seen the offers of £1000 installed boilers on Ebay and to be honest that is a little alarming!

Although all gas safe engineers will charge varying amounts for the work they do, our tip if you are looking for a value install is to use a small but highly recommended local installer. Also smaller companies may not be subject to sales VAT (if their revenue is less than £80k) and can therefore offer a few additional percent off the final price.

Having said that, we always recommend getting a quote from British Gas, to provide you with a high end quote so you can see that you are getting a good deal from a local installer!

How much will it cost to change your boiler?

I hope this gives you a better idea of some of the costs involved, and why changing a old floor mounted system boiler to a modern wall mounted combi might set you back £3,000, whereas switching a relatively modern boiler in the kitchen for a condenser might cost £2,000. Each property is different, but you should now have a bit of an idea what to expect when you get your quote.

Can I get a grant for a boiler replacement?

Installing a new boiler

Are you thinking about getting a new boiler? We have scoured the country for the best tradespeople, so that we can make sure we only recommend those we really trust.

If you would like us to find you a local installer to install a new boiler in your home, just fill in the form below and we will be in touch shortly!

    Interested in getting a new boiler?

    What kind of boiler are you interested in?

    I would like to be contacted by local installers

    I would like to receive occasional news from TheGreenAge