Are you considering replacing your boiler with a brand-new one and want to know the exact costs for the boiler and installation? This boiler installation cost calculator guide will help you find out.

According to the Energy Saving Trust, installing a new, A-rated boiler can save up to £500 annually on fuel costs, depending on your home’s size and thermal performance. Those savings often arrive quietly through lower monthly bills, steadier heating, and a system that no longer feels like it’s one cold snap away from breaking down.

The challenge is that boiler prices are rarely straightforward. Two homes that look similar on paper can receive very different quotes once you consider factors such as installation complexity, pipework condition, controls, and layout. That uncertainty leaves many homeowners guessing whether a quote is fair or inflated.

The boiler installation cost calculator below will help you replace guesswork with clarity by showing how your property, heating system, and installation needs shape the final cost. This makes it easier to make a well-informed decision and plan with confidence, while avoiding unpleasant surprises later.

Key Takeaways on Boiler Installation Cost Calculator:

• Boiler installation costs vary widely depending on your property, boiler type, and installation complexity, rather than a single fixed price.
• A-rated boilers can significantly reduce fuel bills, especially when replacing older or inefficient systems.
• Straight boiler replacements in the same location are usually far cheaper than system conversions or relocations.
• Labour accounts for a large share of the total cost due to safety checks, compliance, and installation time.
• Regional labour rates influence pricing, with costs often higher in London and the South East.
• Extra work, such as power flushing, pipe upgrades, or new controls, can increase costs but often improve long-term performance.
• Using a personalised cost calculator helps set realistic expectations and makes installer quotes easier to compare.

Get Your Personalised Boiler Installation Cost Instantly

How Does the Boiler Installation Cost Calculator Work?

This calculator reflects how boiler pricing works in the real world rather than relying on headline figures or best-case scenarios. Instead of offering a single average price, it adjusts the estimate based on the details that genuinely influence installation costs in UK homes.

By answering a few straightforward questions about your property, existing heating system, and installation requirements, you will see a realistic cost range that separates the price of the boiler itself from the labour and materials needed to fit it safely and correctly. That distinction matters, since installation costs are often where quotes vary the most.

Every input plays a role. Property size affects boiler output. The number of radiators influences pipework demand. Moving a boiler or upgrading controls adds time and complexity. The calculator brings these elements together so the estimate reflects how installers actually price jobs, not how marketing pages simplify them.

The result is a clear starting point for comparison. It gives you enough detail to recognise a sensible quote, question one that feels out of line, and move forward with a better understanding of what your home is likely to need.

What are the Average Boiler Installation Costs in the UK?

Boiler installation costs across the UK tend to fall within broad ranges that reflect common property types and installation scenarios rather than one-size-fits-all pricing.

The Energy Saving Trust notes that the typical cost of replacing a G-rated gas boiler with an A-rated one in Great Britain is around £3,700. For smaller homes such as flats or one-bedroom properties, a straightforward combi boiler replacement often sits at the lower end of the scale, particularly when the existing system is modern, and the boiler stays in the same position.

Medium-sized homes, including typical two- or three-bedroom houses, usually require a higher-output boiler and more installation time, which pushes costs into a higher bracket. Larger family homes with multiple bathrooms often need system or regular boilers, additional controls, and more complex pipework, all of which increase overall installation costs.

The averages provide a helpful reference point, but they are most useful when combined with a personalised estimate. Understanding where your home sits within these typical ranges makes it easier to judge whether a quote reflects genuine installation requirements or includes costs that may not apply to your situation.

What Factors Does the Boiler Installation Cost Calculator Consider?

Factors you need to consider when working out how much a new boiler installation will ultimately cost you include:

Type of Boiler

The type of boiler you choose will affect the final cost.

The main types of boilers installed in UK households include:

Combi or Combination Boilers

Installing a new combi boiler can cost from £1,500 to £4,500. The cost will depend on the boiler type, warranty length, installation complexity, and labour costs in your area.

Combination boilers are by far the most common type of boiler used in UK homes. They can provide hot water on demand and heat water from a single, typically wall-hung unit.

Combination boilers take cold water directly from the mains and do not need a storage tank. Instead, they heat the water as needed.

For this reason, they are also easier to install and ideal for homes with limited space.

Did you know your boiler’s efficiency can impact the energy it uses and, ultimately, your heating bill costs? Check out our guide to the best condensing boilers for more information. 

You may also find our review of the best eco-friendly boilers of interest.

Check out our video on how to vet boiler brands/models in the UK:

New Boiler Cost Guides by Boiler Type: 

• Combi Boiler Costs.
• System Boiler Costs. 
• LPG Boiler Costs.
• Condensing Boiler Costs. 
• Back Boiler Removal Costs. 
• Hydrogen Boiler Costs. 
• Regular Boiler Costs.
• Heat Only Boiler Costs.
• New Boiler & Radiator Costs.

System Boilers

System boilers are also popular in UK homes and ideal for properties with high hot water demand or areas with poor water pressure.

How much you pay will depend on factors such as the brand, required controls, warranty length, additional valves or pumps, and the overall complexity of the job.

System boilers have their own internal pump. The water is fed from the mains and stored in a separate hot water cylinder/tank.

This means they can handle a high hot-water demand, such as when multiple bathrooms are used at once, without a drop in flow rate or pressure.

The costs above are for installing the boiler only and don’t include the costs for new or replacement cylinders.

Heat-Only/Regular/Conventional Boilers

Heat-only boilers, or regular boilers, are older versions of the system boiler and work similarly.

The significant difference is that they do not use an internal pump. Instead, they have a gravity-fed header tank.

Electric Boilers

Electric boilers can be regular, combi, or system boilers powered by electricity from the National Grid, like your other appliances, rather than gas or oil. They’re an eco-friendly alternative suitable for homes without gas access.

They’re highly efficient, easy to install, and release fewer emissions. However, electricity is usually more expensive than gas or oil and is generated by burning fossil fuels.

Combining an electric boiler with renewable energy sources like solar panels or solar thermal can make it a worthwhile investment since you’ll use free electricity.

The table below shows how much you can expect to pay for different types of boilers in the UK:

Type of Boiler/Fuel Source	Cost Excluding Installation	Cost Including Installation	Average Cost Including Installation
Combi Swap	£600 – £2,000	£1,500 – £4,500	£3,000
System Boiler	£500 – £2,500	£1,700 – £5,000	£3,300
Conventional Boiler	£600 – £3,500	£1,700 – £4,500	£3,000
Electric Boiler	£600 – £2,500	£2,000 – £4,500	£2,500
Biomass Boiler	£7,000 – £15,000	£10,000 – £18,000	£15,000

Boiler Brand

As with any other home appliance, some brands are more expensive than others. Some boiler brands use higher-grade components, such as stainless-steel heat exchangers and all-metal parts, rather than plastic components.

In addition, some brands have better reviews, longer warranty periods, and a reputation for superior customer service, which can be especially important in a boiler breakdown emergency.

Wondering which boiler manufacturers performed best? Check out our best boiler brands guide for the full rundown, and if you are trying to determine which is the best boiler installation company, check out our Warmzilla and Boxt reviews.

Warranty Period

Perhaps one of the most important considerations when buying a boiler is the warranty length.

Ideally, you want the boiler warranty to be as long as possible. Not only is this a sure sign of a higher-quality boiler, but it also means you’ll be covered for repairs or a replacement, for extra peace of mind.

Often, you can buy a boiler cheaper, but the warranty period will be much shorter, e.g., 2 years vs. 10-year warranties.

Longer warranties usually feature higher prices, so you must factor this into a boiler installation cost calculator.

Some brands offer a warranty, while others provide a guarantee. While these do sound similar, there is a slight technical difference. A warranty is an agreement between the manufacturer and the customer that the manufacturer will diagnose and repair the boiler, though not necessarily at no cost.

A boiler guarantee is a promise that the boiler will be diagnosed and repaired free of charge.

Do you have a common boiler problem? Check out our quick-fix guide on boiler lockout, boiler ignition faults, boiler PCB faults, faulty diverter valves, and boiler timer issues.

Boiler Manufacturer	Period (Years)	Guarantee or Warranty?
Viessmann	5-10 years	Warranty
Ideal	5-10 years	Warranty
Worcester Bosch	5-10 years	Guarantee
Vaillant	5-10 years	Warranty
BAXI	3-10 years	Warranty

Moving Your Boiler Location

It’s typically cheaper to have your boiler installed in the same place it was. However, you should expect to pay more if you want to move your boiler to a new location, such as upstairs or in the attic.

The reason is pretty simple: moving the boiler means repositioning the pipework, which takes more time and costs more in materials.

Related reading: 

• Boiler service costs.
• How to fix a boiler timer.
• Warmzilla reviews.
• No power to the boiler.

Your Location in the UK

The cost of installing a boiler is determined by the labour required.

This varies depending on your location, the company you hire, the time it takes to install the boiler, and the number of engineers needed.

For example, a combi swap is much quicker, taking around a day to complete, while a back boiler conversion can take around two days and require more than one engineer.

Scaffolding

In some cases, scaffolding will be required to replace your boiler, especially if it’s at a very high level and would be unsafe to reach with a ladder alone.

This is an added cost, since contractors and installers typically rent scaffolding for the installation, which they factor into the job.

It’s worth noting that some companies, e.g., Boxt and Heatable, don’t always charge extra for this, and it’s part of their “fixed price” promise.

Vertical Flue Cost

A vertical flue can cost from £300 to £600.

The boiler flue is a pipe that carries exhaust gases from the boiler to the outside of your home. It helps ensure condensation and the boiler’s emissions are pumped out of your home.

If the flue leaves your property horizontally, you’ll incur no costs. However, if it leaves the property vertically through the roof, it will require more work, resulting in additional fees.

Gas Pipe Upgrade

If you have an old heating system, you’ll need to upgrade the gas piping to comply with current regulations.

Gas pipes with a width of 15mm must be upgraded to at least 22mm, which will incur additional costs of around £250-£400.

Sometimes older pipes must be replaced entirely, especially if they are made of lead. Some installation companies don’t charge for upgrading pipework, so ensure you shop around.

Chemical Flush

A chemical flush will help clear any existing sludge or debris from your heating system, costing from £100 to £150.

Sludge can prevent hot water from flowing to your radiators effectively, making it difficult to heat your home comfortably.

A chemical flush is typical and standard, but you can also get a power flush for up to £500. However, you should be cautious to avoid damaging an old heating system by forcing high-pressure water through it.

Radiators

When fitting a new boiler, inspect your entire heating system, including the radiators.

Radiators wear down over the years. Old radiator models can also be less efficient and perform poorly compared to modern models.

The efficiency of the radiators will directly impact the overall efficiency of the boiler and heating system.

Features like thermostatic radiator valves (TRVs) can enhance control over individual room temperatures, contributing to energy-efficient heating and cost savings.

The price of new radiators can vary depending on size, design, material, and the number you require.

Extras

If you want extras, this needs to be factored into the cost of the new boiler installation.

Any renovations or adjustments you may require when the new boiler is installed are additional factors that impact the costs you are charged for boiler installation.

In some circumstances, additional pipes, valves, or electrical outlets may be required to accommodate the new boiler.

You should anticipate paying more if you need renovations or alterations to the pipes or power source than someone who does not.

Emergency Install vs Pre-Planned Install

If your boiler breaks down suddenly in the depths of winter and you need it replaced as soon as possible, you may be dealing with an out-of-hours emergency install, which will have a premium.

Although it’s not always possible, it’s far better to plan a boiler install rather than waiting until it’s already broken and you need it replaced urgently.

New Boiler Installation Vs Boiler Replacement Costs

Understanding the difference between a straight replacement and a more involved installation is crucial when budgeting for a new boiler. The scope of work significantly affects the total cost.

Straight Replacement

This is the simplest scenario: removing the old boiler and installing a new one in the same location, with minimal adjustments to the existing pipework or flue. Labour time is shorter, and additional materials are rarely required, keeping costs closer to the lower end of the range.

System Conversions

Upgrading from a conventional or regular boiler to a combi system, or converting a heating system type, involves more work. Tanks may need to be removed, pipework rerouted, and sometimes radiators or controls updated. These additional steps increase both labour and materials costs.

Boiler Relocation

Moving a boiler to a new room or repositioning it within the same space adds complexity. It often requires new flue installation, gas pipe upgrades, and additional electrical work. Relocation projects are typically the most expensive type of installation due to the extra time, materials, and regulatory compliance involved.

By distinguishing these scenarios, homeowners can better understand why quotes differ and identify which type of installation applies to their property. This knowledge allows for more accurate budgeting and clearer discussions with installers.

How Much Does a Back Boiler Replacement Cost?

The average cost of a back boiler replacement in the UK is between £2,000 and £2,500.

If you have an old-fashioned back boiler like the Baxi Bermuda (typically found above the fireplace), you’ll need to decommission and remove it. You’ll then install a new boiler, e.g., a combi boiler, in a suitable location.

Similar to a boiler conversion, replacing a back boiler takes more time and labour and requires more materials.

Additionally, if the back boiler is located high up, scaffolding will be required, which can increase costs.

Did you know that not all boiler models are wall-hung? Check out our complete guide on floor-standing boilers here.

Can You Reduce Boiler Installation Costs?

While some installation costs are unavoidable, there are ways to manage expenses without compromising safety or efficiency. Being informed allows you to make choices that reduce unnecessary costs while still achieving a reliable heating system.

Choose the Right Boiler Size

Selecting a boiler that matches your property’s heating and hot water needs avoids overspending on oversized units or struggling with an undersized system that wastes energy.

Keep The Boiler In The Same Location

Relocating a boiler adds labour, pipework, and flue adjustments. Whenever possible, maintaining the existing position can significantly reduce installation complexity.

Plan Optional Extras Carefully

Some add-ons, like magnetic filters or smart thermostats, improve long-term performance but aren’t essential for basic operation. Decide which upgrades offer real value for your home.

Compare Installer Quotes

Getting multiple quotes ensures competitive pricing. Focus on installers who are Gas Safe registered and provide transparent breakdowns rather than simply the lowest upfront price.

Avoid Seasonal Pressures

Booking installation outside of peak demand periods, such as early autumn, can sometimes reduce costs and improve scheduling flexibility. These strategies help you control spending while ensuring the new boiler is installed safely and efficiently, giving you long-term savings and peace of mind.

Boiler Installation Cost Calculator Summary

Replacing or installing a new boiler is a significant investment, but understanding the factors that influence cost can make the process far less stressful. By using the personalised calculator, reviewing typical UK cost ranges, and considering installation complexity, you can approach quotes with confidence rather than uncertainty.

Being informed allows you to make decisions that balance upfront expense with long-term efficiency and reliability. A well-planned installation not only improves comfort and safety in your home but can also deliver substantial savings on fuel bills over time. Always ensure that the installer is on the Gas Safe Register and is qualified to install a gas boiler.

With precise estimates, insight into potential extras, and access to qualified installers, you can move forward knowing your new boiler will be installed correctly, safely, and efficiently, providing warmth and peace of mind for years to come.

FAQs on Boiler Installation Cost Calculator

How Much Does a New Boiler Cost Including Installation?

The total cost of a new boiler, including installation, typically depends on the boiler type, property size, and installation complexity. For most UK homes, prices usually fall within a broad range that reflects both the boiler unit and professional installation. Straight replacements tend to cost less, while system upgrades, conversions, or boiler relocations increase the overall price.

What Is the Labour Cost to Replace a Boiler?

Labour costs vary based on how long the installation takes and the level of work involved. A straightforward boiler replacement completed in a single day usually has lower labour costs than installations that require pipework changes, system flushing, or multiple days on site. Regional labour rates also influence the final figure.

How Much Does It Cost to Remove and Install a Boiler?

Removing an old boiler and installing a new one is generally included within the installation quote rather than priced separately. The cost reflects safe removal, disposal, fitting, commissioning, and testing of the new boiler. Additional charges may apply if the system requires upgrades or modifications.

How Long Does Boiler Installation Usually Take?

Most standard boiler replacements can be completed within one working day. More complex projects, such as changing boiler type or relocating the unit, often take two or more days, depending on the amount of additional work required.

Why Does It Cost So Much to Install a Boiler?

Boiler installation involves more than fitting an appliance. Costs reflect skilled labour, safety checks, Gas Safe certification, system preparation, and compliance with current regulations. The work ensures the boiler operates safely, efficiently, and reliably for years to come.

Is It Worth Replacing a 20-Year-Old Boiler?

In most cases, yes. Older boilers are typically far less efficient than modern A-rated models and are more prone to breakdowns. Replacing a 20-year-old boiler can improve heating reliability, reduce energy bills, and provide better control over your home’s heating and hot water.

Sources and References

• Energy Saving Trust – Boiler types explained
• Gas Safe Register – The official list of gas engineers