Richard Gross
How much does a new boiler cost?
Updated: Sep 2, 2020
Want to know the cost of a new boiler? There’s no short answer to this one, but our director Richard Gross explains how pricing works.

The cost of a new boiler can range from as low as £2,000 to as high as £3,000, but it all really depends on your needs. There are, of course, companies that will offer you quotes for a new boiler at the click of a button, but these don't take into account the specifics of your situation and property.
The question of how much a new boiler costs can only really be answered by having the existing boiler and heating system surveyed by a qualified and experienced heating professional (that's us).
When surveying for a replacement boiler, we would consider the following factors:
How old is your existing boiler?
Is the existing boiler correctly sized?
What type of system is currently installed?
How old are the radiators and valves? Are they in good working order?
Is the water quality on the existing system likely to be poor?
What will be the best way to protect the new boiler from sludge in the heating system?
Can the new boiler be sited in the same location as the existing one, or is it better off located elsewhere in the property?
Does the system meet current energy efficiency recommendations & legislation?
Are the system controls in good working order, or would it be sensible to upgrade them to reduce the risk of failure and/or to increase system efficiency?
Can the current gas supply support the installation of a modern condensing boiler?
Will there be any need to allow for additional heating or hot water capacity when replacing the boiler (eg. due to possible future extensions or the addition of more bathrooms)?
So what is the actual cost of a new boiler?
We can work with almost any reasonable budget but always aim to give the right long term advice to all of our clients. Here's what you can expect to get for the following costs:
Cost for replacing a combination (combi) boiler
Replacing your combi boiler with a brand-new, high-spec Viessmann boiler will This would come with a 7-year warranty and a standard horizontal flue, full powerflush, Dirtmag filter, upgraded heating controls and scale reducer for between £2,000 and £3,400 (incl. VAT). g controls and scale reducer. The cost will vary based on your needs, for example, some systems may not neeed a powerflush or may already have filters and scale reducers installed. Some boilers may also need to use longer flue runs or have vertical flues, which will also have an impact on the overall cost.
To bring costs down, you might decide on a mid-spec Viessmann boiler instead. This would come with a 7-year warranty and a standard horizontal flue, full powerflush, Dirtmag filter, upgraded heating controls and scale reducer for between £2,000 and £3,400 (incl. VAT).
Costs for replacing a regular or conventional boiler
Replacing your regular or conventional boiler with a high-spec Viessmann boiler is likely to cost you between £2,000 to £3,500 (incl. VAT). For this, you'll get the boiler itself, a 10-year warranty, a standard horizontal flue, full powerflush, Magnaclean filter and upgraded heating controls. As above, these costs might vary based on your system's need for a powerflush or the presence of filters and scale reducers.
Top tip: Not sure what type of boiler you have? Find out which boiler type you have here with our guide.
Costs for replacing a system boiler
Replacing your system boiler with a high-spec Viessmann boiler is likely to cost you between £2,000 to £3,500 (incl. VAT). For this, you'll get the boiler itself, a 10-year warranty, a standard horizontal flue, full powerflush, Magnaclean filter and upgraded heating controls. As above, these costs might vary based on your system's need for a powerflush or the presence of filters and scale reducers.
Which boiler brand should you choose?
Although we have used Viessmann boilers – they are our preferred brand – in the above examples above, we do install all makes and models of boilers, so are able to give various options so suit our clients needs.
The most important thing when choosing a new boiler is knowing that it’s going to be installed with care and in line with the manufacturers instructions. Our clients use us because they are safe in the knowledge that they will get expert installation, and be provided with top quality aftercare and 24-hour emergency support when they need it most.
Got more plumbing questions? Read through our FAQs here, or give our expert engineers a call to find out how we can help you.