The Cost of a New Replacement Boiler: All Your Questions Answered!

Welcome to our blog post which will explore the average cost of a new replacement boiler.

We have looked at the benefits of getting a combi or system boiler in previous blog posts. But the cost of a new boiler can overshadow these perks for buyers.

However, as we established in our article on what kW boiler is right for you, a boiler has a lengthy lifespan. This should make you see a boiler as a long term investment for the next 10 to 15 years. 

Without further ado, let us jump straight to the costs of a new replacement boiler.

the cost of a new replacement boiler is unfortunately more than this!

So what is the average cost of a new replacement boiler?

Nowadays, there are three major options when it comes to getting a new boiler. These are a system, combi or regular/conventional boiler.

We should add here that you can no longer replace a back boiler with a new back boiler. They are now obsolete, being expensive to run with little efficiency compared to newer boilers. They are not even in production anymore!

So, examining the most popular installations and the average cost that comes with the major options, we have:

New Boiler InstallationAverage Cost£2,899
Combi to Combi SwapAverage Cost£1,899
Back Boiler to Combi Average Cost£3,299
System to Combi ConversionAverage Cost£2,499
System to System SwapAverage Cost£1,999
Megaflo Unvented BoilerAverage Cost£2,499

Table Credit:

This table of the average cost of a new replacement boiler above includes the cost of installation. Generally speaking, when you buy a new boiler, the main cost is going to be installation, not the actual boiler itself. 

This can obviously vary from the apparent quality of the installer, to the location of your property. Also, the number of engineers who work on the job!

There are a few factors that can determine the overall average cost of a new replacement boiler. 

Aside from brand and model, the most common of these are:

  • If you are changing to a new type of boiler (a conversion).
  • If you are installing the boiler in a different part of your house from the old one.
  • Vertical flue cost; this is the pipe that takes condensation from the boiler outside (£300-600).
  • Possible flush; this is ridding your system of sludge and dirt which could damage your new boiler (£100-400).  
  • Installing a smart thermostat (these heating controls allow you to manage your boiler with ease. They can cost anywhere from around £100-300). 
  • The company you chose to do the installation. 

In essence, the more simple and straightforward the boiler installation, the cheaper it will be. If you are converting to a new type of boiler, this will involve more work, thus be pricier. If your new boiler needs to be in an alternate room it will simply cost more.

You don’t have to worry about the kW of a boiler, as we have covered this here. It is important you get this part right as it’ll save you money on your energy bills. 

Examining the cost of a new replacement boiler: System Boilers

A system boiler, as detailed in our blog, can heat water straight from the mains. It also stores hot water in a cylinder tank so you can use hot water at multiple sources. This is to ensure no pressure is lost and plenty of people have hot water at once!

They are better suited for larger properties that have multiple bathrooms and en-suites. 

See our system table below:

General Average Cost £1500-3000
Cost of 1-day Replacement (Straight Swap)£1,950
Cost of 2-day Replacement (Replacing Old Boiler and Water Tank)£4,200
Cost of 2-3 day Replacement (Replacing a Combi with a System Boiler)£4,600

Figure source:*

As you can see, the cost of a simple swap with an existing system boiler is relatively cheap. However, it can prove expensive to install a system boiler over an older and different model. 

The table prices are based on the assumption that the boiler is going to the same spot as the old one.

Examining the cost of a new replacement boiler: Combi Boilers

A combi boiler is an all in one unit. The water is drawn from the mains and heated directly through the boiler. They are the most popular model of boiler in the UK at the moment. This is due to being compact (can practically fit in a cupboard) and can run on gas or electric. 

They tend to be particularly popular with smaller home and flat owners. This is due to the water pressure weakening if being used at multiple showers/taps. Looking at our combi table:

General Average Cost £500-3500
Cost of 1-day Replacement (Straight Swap)£2000
Cost of 1.5-day Replacement (Replacing an Old Combi Boiler, but in a New Location)£2,600
Cost of 2-3 day Replacement (Replacing an Old Regular Boiler and Tank with a Combi)£3,200

Figure Source: *

As the chart shows, the most expensive option is the replacement of an old boiler with a combi. This is because firstly, the old boiler and tank obviously have to be removed. Then new pipework must be laid for the new combi boiler. 

But this will hopefully save you considerable space in the house and will save you going to the attic to fix the boiler!

Naturally, the price can also be dependent on the location. Using a premium agency in London, for example, will see the price hiked. 

Examining the cost of a new replacement boiler: Regular Boilers

The traditional type of “heat only” boiler is still popular in large homes, although becoming less so than the newer combi. It has hot and cold storage tanks, usually in the loft/attic, which take up a lot of room. But it can provide a large amount of hot water which has been stored up.

Looking at our regular boiler table:

General Average Cost£400-2500
Cost of 1-day Replacement (of Old Heat Only boiler, in the Same Spot£1,750
Cost of 2-day Replacement (of Old Heat only boiler, but in a new spot)£2,200

Figure Source: *

The cost of the general boiler is this particular scenario is in fact relatively cheap. It can be as low as £400 for a small heat only boiler. Additional cost, aside from labour, is resultant of potentially having to move cylinder and other equipment to a new location. 

Why is the cost of a new replacement boiler so high?

Although it can be quite a sting initially splashing out on a new boiler, in the long run it is a money-saving move. 

According to the Energy Saving Trust, the average cost of a new boiler is around £2,300. But after this, you could be saving up to £350 a year with your new A-Rated boiler. 

To stick with a current old model could be costing too much in excess energy bills and repair costs. Boiler breakdowns and repair cost UK households an unbelievable £725m in 2017. Many older boilers have been oversized which is no longer recommended.

Greater efficiency in your boiler will reduce carbon emissions, improve your house value and lower your energy bills. With the efficiency of the newer models of boiler running at around 90%, this is a vast improvement over the old. An ancient boiler would be lucky to have an efficiency running at half of that. 

Do I need to shoulder the cost of a new replacement boiler?

Think you might need a new boiler but aren’t entirely sure? If you have an old model of boiler you are probably experiencing or beginning to experience frequent breakdowns.

Here are a few factors worth considering if you aren’t sure:

  • If it is costing you significant sums of money to repair your boiler.
  • If your boiler is over 10 years old. Considering the lifespan of a boiler is 10-15 years, an older model at this age will be starting to wear. 
  • The boiler has ineffective efficiency and costing more than it should to run. Or if it is not heating your home properly through your radiators.
  • If you are annoyed by the boilers current location in your household. 

Judging by a few of these, you can certainly persuade yourself to consider a new boiler.  The investment into a boiler will relief a lot of stress and unnecessary financial pain maintaining an older one. 

Examining the cost of a new replacement boiler: Niche Types of Boiler

renewable energy off-grid homes sometimes have niche types of boiler

Besides the main types of boiler we have examined in this blog post, there are a few different models. Here we examine some alternatives to the popular aforementioned trio. 

Although expensive, the following add significant value to a property and are very much a sign of the future:

Biomass Boiler Average Cost£7-13,000
Condensing BoilerAverage Cost£1200-2500
Wood Pellet Boiler Average Cost £4-18,000

A biomass boiler allows you to have a positive impact on the environment. By burning logs. The carbon dioxide emitted by the burning wood is the same that was absorbed by the tree when it was growing. So supposedly it is a carbon-neutral process!

A condensing boiler uses the waste heat from the flue gases to preheat water you have stored. As a result, they are extremely efficient. 

Lastly, a wood pellet boiler uses “seasoned” fuel that has been stored for a year. This is too rid the wood of moisture to prevent the release of so much pollution.

We hope our blog post was helpful in finding you the average cost of a new replacement boiler! Please get in touch if you have a further question we could help with. 

If there is anything else you are seeking an answer to, it is worth checking the rest of our blog. The answer may be there.

Archie Everard

Archie is a content writer at Homesage, who has enjoyed freelance writing before and after his time at Oxford Brookes. Obviously he loves boilers most of all, but also enjoys reading, football and going to the pub!