The initial price for a brand new boiler will land anywhere between £500 and £2,500, but this will only include the boiler itself.

There are many deciding factors to consider before landing on a final figure. It doesn’t have to feel like climbing Mt. Everest when you’re trying to work this out!

How much is a new combi boiler?

A typical price for a new combi boiler will be anywhere from £1,500 to £3,500.

REMEMBER: Every modern boiler built in the last 12-15 years, regardless of boiler type, is a condensing boiler.

Further Information on Combi Boilers:


Combi boiler prices


BRANDMODELOUTPUT (KW)PRICEFUEL
ViessmannVitodens 100-W Combi26£1,017.98 (inc VAT)Gas/LPG
Worcester BoschGreenstar 25i Combi25£935.15 (inc VAT)Gas/LPG
VaillantecoTEC pro Combi24£969.98 (inc VAT)Gas/LPG
GrantVortexBlue Floor Standing Combination Boiler Oil ErP36£2,764.99 (inc VAT)Oil
ViessmannVitodens 050-W29£807.11 (inc VAT)Gas/LPG
IMPORTANT: These prices are from an online plumbing wholesaler for the boiler only. They do not cover installation costs or other extras.

How much is a new regular boiler?

The cost of a regular boiler by itself will be between £500 and £3,000. But just like every other boiler type, there are more aspects to the installation to consider such as the inclusion of a hot water storage tank or cylinder before landing on the final cost of a new boiler.


Regular boiler prices


BRANDMODELOUTPUT (KW)PRICEFUEL
ViessmannVitodens 100-W Compact Regular26£954.96 (inc VAT)Gas/LPG
Worcester BoschGreenstar 24Ri Regular Boiler24£932.56 (inc VAT)Gas
VaillantecoTEC Plus 424 Regular24£1,030.98 (inc VAT)Gas
GrantVortexBlue 26kw Kitchen/Utility Floor Standing Regular Boiler Oil ErP36£1,793.98 (inc VAT)Oil
ViessmannVitodens 050-W29£954.96 (inc VAT)Gas/LPG
IMPORTANT: The prices above are from an online plumbing wholesaler for the boiler only. They do not cover installation costs or other extras.

How much is a new system boiler?

The cost of new system boiler by itself can vary, but will land somewhere between £500 and £1,500. A system boiler installation will need extra features and services to ensure success.


System boiler prices


BRANDMODELOUTPUT (KW)PRICEFUEL
ViessmannVitodens 100-W System Boiler26£1,077.98 (inc VAT)Gas/LPG
IdealIndependent 24KW System Boiler24£872.98 (inc VAT)Gas
VaillantecoTEC Plus 624 System Boiler24£1,220.98 (inc VAT)Gas
GrantVortexBlue 26kw Kitchen/Utility Floor Standing Regular Boiler Oil ErP36£1,997.98 (inc VAT)Oil
IMPORTANT: The prices above are from an online plumbing wholesaler for the boiler only. They do not cover installation costs or other extras.

It’s a good to learn about the different boiler types before looking at the cost of a combi boiler specifically. Below is an explanation of all types of combi boiler installations with their average cost range.

How much is a regular to combi boiler installation?

The average open vent to combi boiler installation cost is between £1,800 and £3,800* inc. VAT
*Depending on the options you choose.
A decade or so ago we didn’t have powerful combi boilers. The only option was to either get rid of attic tanks and convert to a system boiler or replace the old open vent boiler. Now we have larger capacity combi boilers (up to around 42kW) and storage combi boilers for larger properties.

What’s included in a regular to combi installation?

  • Brand new modern condensing combination boiler
  • Horizontal or vertical flue
  • Microbubble deaerator (if relevant)
  • Magnetic filter
  • Limescale filter
  • Boiler Plus compliant programmable thermostat or an internet-enabled learning thermostat
  • North-facing weather compensation
  • Chemical flush & inhibitor
  • Associated pipework
  • Up to 10-year warranty
  • Commissioning of the boiler and benchmarking
  • Building Regulation notification with certification including landlord certificates
  • Handover & induction on the boiler and controls

How much is a sealed system to combi boiler installation?

The average system to combi boiler installation cost is between £1,800 to £3,800* inc. VAT
*Depending on the options you choose.
Sealed System boilers only need the hot water cylinder for domestic hot water storage

What’s included in a sealed system to combi installation?

  • Brand new modern condensing combination boiler
  • Horizontal or vertical flue
  • Microbubble deaerator (if relevant)
  • Magnetic filter
  • Limescale filter
  • Boiler Plus compliant programmable thermostat or an internet-enabled learning thermostat
  • North-facing weather compensation
  • Chemical flush & inhibitor
  • Associated pipework
  • Up to 10-year warranty
  • Commissioning of the boiler and benchmarking
  • Building Regulation notification with certification including landlord certificates
  • Handover & induction on the boiler and controls

How much is an old combi to new combi installation?

The average old to new Combi Boiler Installation Cost is between £1,600 to £3,500* inc. VAT
*Depending on the options you choose.
One of the quickest installation options available is to replace your old combi boiler with a new one. Because your central heating system is already set up around a working combi, the process is much smoother. In some cases, the gas run will have to be upgraded to 22mm for modern condensing combi boilers.

What’s included in an old combi to new combi installation?

  • Brand New, Modern Condensing Combination Boiler
  • Horizontal or Vertical Flue
  • Microbubble Deaerator [If the Client Wants it]
  • Limescale Filter
  • Boiler Plus Compliant Programmable Thermostat/Internet Enabled Learning Thermost
  • Chemical Flush & Inhibitor
  • Associated Pipework
  • Registration of Extended 7-10 Years Warranties
  • Commission & Test to MFI & Complete Benchmark
  • Building Regulation Notification with Certification including Landlord Certificates
  • Hand Over & Induction on Boiler, Controls & Best Usage

How much is a Back Boiler to New Combi Boiler Installation?

new combi boiler installation cost

The average Back Boiler to New Combi Boiler Installation Cost is between £2,200 to £4,500 inc. VAT
*Depending on the options you choose.
There’s a bit more work involved with this one.  The old back boiler will be decommissioned and removed if you prefer. In most cases, this installation connects to a vertical flue instead of a horizontal flue, adding more to the cost.

What’s included in a back boiler to new combi installation?

  • Brand New, Modern Condensing Combination Boiler
  • Horizontal or Vertical Flue
  • Microbubble Deaerator [If the Client Wants it]
  • Limescale Filter
  • Boiler Plus Compliant Programmable Thermostat/Internet Enabled Learning Thermostat
  • Chemical Flush & Add an Approved Inhibitor
  • Associated Pipe Work to Complete Installation
  • Registration of Extended 7-10 Years Warranties
  • Commission & Test to MFI & Complete Benchmark
  • Building Regulation Notification with Certification including Landlord Certificates
  • Hand Over & Induction on Boiler, Controls & Best Usage

How much is Full Central Heating with a New Combi Boiler?

The average Central Heating and new Combi Boiler installation cost is between £4,000 to £6,000 inc. VAT
*Depending on the options you choose. Includes radiators, pipe runs, gas upgrades etc.
Basing your new central heating system around a combi boiler can cost a lot more compared to only replacing the combi boiler.

What’s included in a full central heating and new combi boiler installation?

  • Brand new Condensing Combi Boiler
  • Horizontal or Vertical Flue
  • Magnetic Filter
  • Microbubble Deaerator [If the Client Wants it]
  • Limescale Filter [If Required]
  • Boiler Plus Wireless Digital Programmable Thermostat/Internet Enabled Learning Thermostat
  • North Facing Weather Compensation [If workable]
  • New Gas Run
  • Radiators
  • TRV (Thermostatic Radiator Valves)
  • Lock-Shield Radiator Valves
  • Chemical Flush & Inhibitor
  • All Associated Pipe Work
  • Registration of Extended 7-10 Year Warranties
  • Commission & Test to MFI & Completion of Benchmark
  • Building Regulation Notification with Certification including Landlord Certificates
  • Hand Over & Induction on Boiler, Controls & Best Usage

What’s included in a new boiler installation?

Let’s take a look at how these features can affect the price of a new boiler:

1. Magnetic Filter

Magnetic Filters help catch most of the magnetite sludge that circulates around your heating system. This sludge usually sits at the bottom of your radiators, and can damage to your radiators’ and your boiler’s components.
Benefits include:
  • Reduced energy bills
  • Drastic improvement to your boiler’s efficiency
  • Reduced likelihood of frequent/expensive repairs
  • Extension of boiler’s lifespan
  • Reduction of carbon footprint
Want to know more? Read our detailed guide.

2. Hardwater Filter

If there’s a build up of limescale in your system, the flow of water becomes restricted. When this occurs, the boiler’s internal heat exchanger will rise in temperature. If it gets hot enough, the water starts to steam, causing those ‘gurgling’ noises to come from your boiler, so getting a filter is a no-brainer.
Unsure of the water hardness in your area? Take a look at the map below!

3. Power Flush/Chemical Flush

You’ll need a Chemical or Power flush arranged to help clear any sludge you already have in your system.

What is a chemical flush?

Using rapid heat cleaner chemicals, chemical flushes break down and disperse the sludge that builds over time. With a strong final flush and added inhibitor, your system gets a much-needed clean to improve its lifespan and quality.

What is a power flush?

A powerflush is a similar process, but includes the use of a machine to help push the sludge out the system. The machine has a pump attached to your heating system which sends powerful chemicals through your pipework at high speed. They’re an effective method of clearing your system, but they’re not ideal for weaker, older systems.

4. Relocating the boiler

new boiler installation

You might find that during the planning process for your new boiler, there are better places for it to be positioned. Any position change for your new boiler will add more to the cost, due to extra pipework and manual labour.
As a general rule, it’s much cheaper to keep your new boiler in the same location. If you want it moved, you can expect it to add around £300 to £700 to the total cost of a new boiler. 

5. Boiler Size/kW Rating

The bigger the kW rating a boiler has, the more the new boiler cost will be.  The physical size of a boiler is fairly consistent across manufacturers and it is not actually based on the number of radiators you have either.
Cheap boilers can cost as little £400, with the larger models costing anything up to and even beyond £2,000.

6. Upgraded heating controls

Nest Learning Thermostat
Having a high-quality thermostat is vital for allowing users full control over their central heating system.
Modern thermostats are becoming increasingly advanced in their capabilities. Examples include the Nest Learning Thermostat, which adapts to your living behaviours to help save more money in the long run. A basic thermostat will cost just £20, while a more complex, Wi-Fi controlled thermostat will cost between £200 to £300.
For a comparative look at two of the best thermostats out there, check out our Nest vs Hive blog post.

7. Gas Upgrade

If your gas pipework is getting an upgrade, it’ll be moved up to 15mm in diameter, similar in size to a cuban cigar.
Speaking with an expert about your new boiler installation plans is the best way to find out if you’re due a gas upgrade or not. If the installer of your current boiler failed to address this issue, then the installation would have been carried out illegally.
Upgrading your gas piping can increase the cost by anything between £200 and £500, but it depends on how difficult the installation would be.

8. Flue Position

vertical flueIn most properties, it’s more common for a boiler flue to exit the building horizontally.

For some, the flue will need to be redirected to exit your property vertically (often through the roof). This process will incur further costs, not so much because of labour, but because of the materials required. For the supply and installation of a vertical flue from a horizontal flue, you can expect to be charged between £300 -£400.

9. Condensate Pump

On occasion, a boiler will be installed at the centre of the property (usually in an airing cupboard). When this occurs, you won’t have the access required for an internal condensate pipe to be installed.
The solution? Have a condensate pump installed – this means the condensate (acidic water) can be pumped up into the attic space. It can then be directed down a soil stack or downpipe. This can cost an extra £180 to £300. Costs such as this must be included to ensure your new boiler installation complies with current boiler and flue regulations.
For more information on the condensate pipe, please click here.

 10. Additional Scaffolding
Although it depends on the installation, there may be occasions where hiring scaffolding is required. If your chosen installer is professional and experienced, they’ll inform you of this beforehand. For any installation, always make sure you fully understand your terms and conditions.

11. Additional unplanned work

It’s the last thing you want to be doing after an install – It’s not unheard of that extra work is needed to ensure a successful installation. This could range from scaffolding needed for wall access, or a change in space availability.
The best way to avoid any issues surprise additions to the cost, is to be completely honest and transparent with your installer.
By communicating very clearly from the beginning what you’ve agreed to, you can avoid any confusion during the planning process. Be honest with your installer, and you’ll be able to use their knowledge and experience to ensure you get a boiler that’s right for you and your property.

12. Boiler Suppliers And Warranty Choices

Boiler manufacturers offer their products for different price brackets. Along with this, a warranty can range from a single year to a whole decade. Although larger brands will be more expensive, they also come with better warranties.
Depending on its length, a warranty could cost between £150 and £300. The cost of installing a new boiler varies from region to region, so choosing the right company is definitely needed. Depending on who you choose – you can expect to pay anything from £60 to £100.

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