How much does a new boiler cost in 2025?

Our new boiler cost guide covers everything you need to help budget for replacing your boiler. We include the average cost of a new boiler, installation, additional expenses, and the financial support available.

The easier way to book quality trades

Download app

Your boiler is a key part of your home's heating system. However, most boilers have a lifespan of 10-15 years, after which time they can start costing you money.

An older boiler is generally less efficient and can lead to higher energy bills. It's also more likely to break down, so you could be shelling out for boiler repairs more often than you'd like.

So if you think it could be time to replace your current boiler, we're here to help. We'll guide you through the costs associated with a new boiler and help to connect you with approved, certified trades you can rely on for installation.

How much does a new boiler cost?

The cost of a new boiler will vary depending on several factors including the type and size of the boiler, the manufacturer, the fuel type, and the complexity of the installation.

The costs outlined in the table above should be used as a guide only.

• New boiler costs generally sit between £1,200 - £10,000. This is for supply only, not including installation

• With labour and typical extra expenses included, you can usually expect your total bill to be between £3,000 - £15,000

For an accurate new boiler price, contact an approved heating engineer for a quote.

Contact or pay a trade through Checkatrade and you’re covered by our 12-month guarantee of up to £1,000*

* Eligibility and T&Cs apply

Average costs by boiler type

There are several different types of boilers available, including combi, system, conventional, electric, and biomass.

In this section, we look at new boiler prices by type, their running costs, and the pros and cons to be aware of.

1. Combi boiler costs

The average cost of a combi boiler is £1,500 (not including installation).

A combi boiler is one of the most popular types of boiler in the UK because it provides both heating and hot water on demand and only needs a single unit, i.e. there's no need for a separate hot water cylinder.

Gas combi boilers are the most popular choice in the UK, but you can also get oil, LPG and electric combi boilers:

• Gas combi boilers use natural gas and are a common choice for any home that’s connected to the gas network

• Oil combi boilers are an option for homes without an existing gas connection and use an oil storage tanker

• LPG combi boilers use liquefied petroleum gas (or LPG) and are an energy-efficient way of providing hot water

• Electric combi boilers function slightly differently as they heat water by passing it over a hot element instead of burning fuel

The average cost of replacing a combi boiler

• Replacing an old combi boiler with a new one in the same location costs around £2,500 - £4,000(supply and install)

• Replacing a system boiler with a new combi boiler costs on average £4,000 (supply and install)

• Replacing a conventional boiler with a new combi boiler costs on average £4,000 (supply and install)

Switching from one type of boiler to another can require more work and additional parts, so expect to pay more than if you're replacing like-for-like.

Pros of a combi boiler

• High energy efficiency

• Lower energy bills

• Compact size - perfect for small properties

• Easy to install

• Hot water on demand

Cons of a combi boiler

• Not suitable for large homes with high demands

• Can be incompatible with old pipework

• Not good for homes with low water pressure

Gas combi boiler cost

The average gas boiler cost for supply and installation is £3,000.

Pros: Gas combi boilers are energy-efficient and compact, meaning lower energy bills. You can also expect hot water on demand, which is a huge plus during the colder months.

Cons: Unfortunately, gas combi boilers are better suited to smaller homes and can be incompatible with old pipework.

Gas combi boiler running cost

On average, expect the running cost of a gas combi boiler to be around £120 per month.

Electric combi boiler cost

The average electric combi boiler cost for supply and installation is £3,000.

Pros: Electric combi boilers are usually more compact, quieter, and cheaper to install than a gas boiler as there’s no gas water pipe or flue.

Cons: Electric combi boilers are also better for the environment, making them ideal if you’re looking for a cleaner alternative to gas.

Electric combi boiler running costs

While these boilers are quick and easy to repair, electric combi boiler running costs can be expensive.

Based on the UK average of 24.50p per kWh, running a 12kw electric boiler at 70 hours a month will cost £206 per month.

In comparison, the average monthly gas boiler cost is about £120 per month.

This is simply because the cost of electricity is higher than gas. But, as the efficiency of electric boilers is far higher, you’ll get more heat generated for the same cost.

As a result, it may mean that it’s cheaper to heat your home with an electric combi boiler. This will be impacted by a number of factors, including the size and layout of your home, how well-insulated it is, and your electricity tariff.

Oil combi boiler cost

The average oil combi boiler cost for supply and installation is £4,000.

Pros: If your property isn’t connected to the main gas or electric network, an oil combi boiler can be a good alternative for heating your home and water.

Cons: The cost of oil boiler installation is often higher than some other heating systems, such as electric boilers.

Oil combi boiler running costs

When it comes to running costs, oil is typically more expensive than gas and is also less efficient.

Cost of running gas central heating

In the UK, most of us are connected to mains gas. But if you’re off the main grid, you’ll need to look at alternatives. So, what exactly are the options when it comes to gas central heating and what does it cost?

Learn more

2. System boiler costs

System boilers supply your central heating and hot water via a storage cylinder. This type of boiler is fed by the mains water supply.

• Upgrading to a newer system boiler cost is around £3,000 (supply and installation)

• However, a new high-end system boiler could cost around £2,500 + (supply only)

As with combi boilers, system boilers can be fuelled by oil, gas, or electricity:

• A new oil system boiler costs starts at around £2,000 (supply only)

• The average new gas system boiler cost is around £1,500 (supply only)

• The average new electric boiler cost (system boiler) is £1,750 + VAT (supply only)

Pros of a system boiler

• More compact than conventional boilers as there's no need for a cold water tank

• Have the capability to supply warm water to multiple taps at the same time

• Good mains water pressure

• Can be compatible with solar energy

Cons of a system boiler

• Hot water is heated up before use, so you will need to think in advance about when you will need it

• Larger than combi boilers

• You will have a limited amount of hot water depending on the size of your tank

3. Conventional boiler costs

If combi and system boilers don’t fit your requirements, there’s the option of conventional or ‘heat only’ boilers.

These are often cheaper than other boilers but require a hot water cylinder and a cold water tank. Conventional boilers heat previously stored water until it is ready to be used and are a great option for large homes.

• On average, a conventional boiler will set you back around £3,000 (supply and installation)

The size you need will depend on your home's size and budget.

Pros of a conventional boiler

• A great way of providing warm water to multiple showers or taps

• Easy maintenance

• Can still provide hot water if mains pressure falls

• An immersion heater can be used to make sure the hot water supply continues even if the boiler breaks down

Cons of a conventional boiler

• The need for hot and cold feed tanks means these boilers take up more space

• They don't always supply the best pressure for showers

• Less efficient than other options - heating loss can occur if water is stored for long periods

• During high periods of demand, you may run out of hot water

It's worth noting that certain ‘heat only’ boilers do not supply hot water, so they'll only heat your home.

For professional advice, contact a local heating engineer to select the best boiler for your needs.

4. Condensing boiler costs

Condensing boilers come in two varieties - regular and combi.

• A regular boiler has a hot water tank and can supply energy to a large-sized house

• The combi-condensing boiler, on the other hand, does not have a water tank. This makes it more compact, making it suitable for smaller houses and flats

As a ballpark average, the cost of a new condensing boiler is normally around £1,500 (supply only).

Installation costs for a condensing boiler are usually around £1,500.

The installation cost may vary based on your circumstances and the type of boiler you choose.

Pros of a condensing boiler

Condensing boilers are known as high-efficiency boilers.

Instead of allowing heat to be wasted in the flue, these boilers are designed to not only trap the heat but also use the latent heat from condensation.

As a result, these boilers are up to 90% more efficient. And the cost of a condensing boiler is not very high either. The pros include:

• High efficiency

• Lower energy bills

• More eco-friendly

Cons of a condensing boiler

• Higher initial cost

• More complex systems - more potential to go wrong

• May require more maintenance

5. Biomass boiler costs

On average, the price of a biomass boiler is around £10,000 (supply only). The cost of a biomass boiler is considerably more than other types of boiler.

However, before dismissing this option, you may be encouraged to learn that biomass fuel costs are lower, they're eco-friendly, and government grants are available to help with the cost of installation.

The average total costs of supplying and installing a biomass boiler are:

• Manually-fed biomass boiler (logs) - £19,000

• Automatically-fed biomass boiler (pellets) - £31,000

Biomass boiler installation costs start from around £5,000 for a small domestic boiler.

Biomass boiler fuel costs per tonne

A biomass boiler, unlike a gas or oil boiler, uses wood pellets that have been sustainably sourced. Here are some of the average fuel costs per tonne for a biomass boiler in the UK:

• Wood chips – £175 per tonne

• Wood logs – £650 per tonne

• Wood pellets – £750 per tonne

Biomass boiler fuel costs per kWh

To help you weigh up the ongoing running costs of a biomass boiler, here are the equivalent fuel costs per kWh:

• Biomass woodchips – 4.17p per kWh

• Biomass logs (kiln dried logs) – 12.75p per kWh

• Biomass pellets – 15.31p per kWh

Pros of a biomass boiler

• Uses renewable energy

• Lower carbon footprint

• Government grants are available to help with the cost of installation

Cons of a biomass boiler

• Higher initial installation cost

• Significant space needed for fuel storage

Cost of new boiler installation

We always recommend hiring a qualified heating engineer who is accredited to work with the type of boiler you choose for your boiler installation.

• Gas boilers must be installed by a Gas Safe Registered engineer

• Oil boilers must be installed by an OFTEC registered technician

• Electric boilers are best installed by a boiler installation company that will have all the skills necessary for dealing with plumbing, electrics, and gas (if disconnecting an existing gas boiler)

Some people wonder whether a plumber can fit a new boiler. Plumbers can install boilers, but only if they have specific qualifications to offer boiler fitting services.

On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.

New boiler installation cost - hourly rates

When it comes to the cost of new boiler installation, you'll find most boiler fitters charge a day rate. The average rate for a boiler engineer to install a new boiler is about £300 per day.

To help budget for how much it costs to fit a boiler - labour only, here are the average timeframes for new boiler installation:

• A simple, like-for-like boiler installation: 4 - 6 hours

• Converting a regular boiler to a combi boiler: 1.5 - 2 days

• Moving the location of the boiler: variable

Factors that can affect the cost of new boiler installation

The price you’ll pay for your boiler installation will vary, depending on several factors, including:

• Type of existing boiler system

• Whether you're changing fuel types e.g. gas to electric

• Make and model of the new boiler

• Warranty length

• The complexity of the installation

• Any new pipework that's needed

• If the boiler needs to be moved

• Any prep work needed ahead of fitting the boiler

• Where you live (e.g. it's typically more expensive to fit a new boiler in London and the South East than in other parts of the country)

Additional costs with boiler installation

Some homeowners choose to include additional elements when getting a new boiler fitted, which comes at an extra cost. These include:

Powerflushing

Before installing a new boiler, a power flush of your heating system is recommended to clear out any dirt or sludge that's built up over time. This can help to avoid boiler breakdowns.

Powerflushing the central heating can cost around £1,000 inc VAT. Check with your installer whether this cost is included in their quote as many boiler manufacturers require it.

Magnetic filters

Installation of magnetic filtering systems such as MagnaClean, can improve heat efficiency and reduce bills.

Magnetic filters typically cost between £60 - £160 with £50 - £150for installation.

Thermostats

Thermostats are another cost, with many now choosing to upgrade to a wifi-enabled heating controller such as Nest, Tado, or Hive, at a cost of around£150 (supply only).

New radiators

New radiators have proven to be up to 50% more efficient than radiators that are 10+ years old. For this reason alone, it's sometimes best to incorporate the cost of a new boiler and radiators at the same time.

On average, you would spend around £200 on labour costs to remove and replace a double-panel radiator.

For more information, check out our guide to the cost of removing and replacing radiators.

Central heating installation cost guide

A new central heating system is a big investment for any homeowner or landlord, and the price can vary depending on the type of boiler or heater, the number of radiators and other key components. It can cost anything between £2,300 and £5,500 to have central heating installed, depending on fuel source, boiler location and property characteristics.

Learn more

Total cost of a new boiler and its installation

So how much is the average cost of a new boiler AND installation combined?

As we've already outlined, the cost of a new boiler will depend on the type of boiler you choose, various factors surrounding installation, and whether you select any extras such as new rads, magnetic filters, or wifi-enabled controls.

However, digging into the type of installation you require does uncover some further variance in cost.

For example, whether you're replacing the boiler like-for-like, converting it to a different type, or moving it to a new location.

Below, we outline some average prices for the cost of a new boiler and installation for each of these scenarios.

How much does it cost to replace a boiler in the UK?

To replace a combi boiler with another combi boiler costs on average £2,500 - £4,000 (supply and installation).

How much does a boiler conversion cost?

Converting an older boiler to a more modern, efficient type is a smart move. Here are some typical example costs:

Regular to combi boiler conversion cost

Converting a regular boiler to a combi boiler costs around £4,000 (supply and installation) and usually takes about two days.

The cost includes the price of laying new pipework as well as removing and discarding your old boiler and water cylinder.

System-to-combi boiler conversion cost

If you want to replace your system boiler with a combi boiler, your boiler conversion cost will be about £4,000 (supply and installation). This conversion will take up to around three days.

Back boiler-to-combi conversion cost

The average back boiler to combi boiler conversion cost is around £4,000 (supply and installation).

The total cost will depend on several factors, including the new boiler you buy, the location of the existing boiler, and any new pipework needed.

Cost to move a boiler

If you're in the market for a new boiler, it could be a good time to consider moving its location.

The ballpark labour cost to move your boiler will be around £1,000.

The cost will largely depend on the complexity of the job. The more complicated an installation is, the more it will cost.

Our guide to the cost of moving a boiler contains more detailed information.

Popular boiler manufacturers

The best boiler for your home will depend on various factors, including the size of your home, the type of heating system you have, and your budget.

The likelihood is that you'll often be choosing between the UK's leading boiler brands: Worcester Bosch, Vaillant, Alpha, Viessmann, and Ideal.

We've put together an overview of those five brands for you.

Worcester Bosch

• Founded: 1962 in the UK (becoming part of the Bosch Group in 1996)

• Reputation: A solid British boiler brand that provides reliable and energy-efficient boilers

• Performance: Worcester Bosch boilers are renowned for their high-efficiency ratings, with many of the boiler models in their Greenstar range boasting an ErP rating of 'A' for heating and hot water

• Reliability: Customer satisfaction is high on Worcester Bosch's agenda and their boilers are well-known for their excellent reliability and longevity – resulting in them winning the Which? Best Buy award

• Price: Although Worcester Bosch boilers aren't the cheapest on the market, their slightly higher prices are often justified by their solid reputation of quality and reliability

• After-sales support: When you buy a Worcester Bosch boiler you'll typically be given an extensive warranty – some of their models come with up to 10 years of cover (when installed by a Worcester Accredited Installer)

Vaillant

• Founded: 1874 in Germany – Vaillant introduced the first-ever gas-fired central heating system and the combi boiler

• Reputation: Innovation and sustainability are the name of the game when it comes to Vaillant, and they've become extremely popular for their eco-friendly and energy-efficient heating solutions

• Performance: Vaillant consistently achieves high-efficiency ratings with their boilers, with many models gaining an ErP 'A' rating for heating and hot water

• Reliability: Over the years, Vaillant boilers have become well-known for their reliability and high quality, winning them the Which? Best Buy award on multiple occasions

• Price: Models available for various budgets, they're not usually the cheapest but their quality and reliability explain the slightly higher price tags

• After-sales support: Depending on the model of the boiler, Vaillant offers warranties from 2 to 10 years for their boilers – when installed by a Vaillant Advance installer

Alpha

• Founded: 1966 and is part of Italian heating appliance manufacturer Immergas (market leader for boilers in Italy)

• Reputation: Alpha has built a reputation in the UK boiler market as a brand focused on innovation, energy efficiency, and high-quality products

• Performance: Alpha boilers typically boast excellent energy efficiency and many models use advanced technology to optimise their heating performance

• Reliability: Their products are designed to last and Alpha has a strong focus on delivering quality products and achieving high levels of customer satisfaction

• Price: Alpha typically offers competitive prices for decent-quality boilers and has become popular with homeowners on limited budgets

• After-sales support: Most Alpha boilers come with a warranty of 5 to 10 years when installed by an Alpha Approved Installer. They also provide a very good level of customer service for all other after-sales support

Viessmann

• Founded: 1917 in Germany

• Reputation: Viessmann has become best known for using cutting-edge technology, as well as their commitment to sustainability – offering a wide range of energy-efficient boilers

• Performance: Viessmann boilers consistently achieve high-efficiency ratings with many models gaining ErP 'A' ratings for heating and hot water

• Reliability: Viessmann is generally considered to be an extremely reliable boiler manufacturer, with a strong track record of excellent customer satisfaction

• Price: With their reliability and high-quality products comes a slightly higher price tag than some of their competitors. That said, Viessmann does offer options for a range of budgets

• After-sales support: Many Viessmann boilers come with a comprehensive 7-year parts and labour warranty as standard (as long as the boiler is registered within 30 days of purchase/installation)

Ideal

• Founded: 1906 in the UK

• Reputation: Ideal boilers are renowned for their commitment to innovation, quality, and reliability for all their products

• Performance: When buying an Ideal boiler you will most likely be buying an extremely energy-efficient boiler with impressive performance – many of their models feature an ErP 'A' rating for heating and hot water

• Reliability: Ideal boilers have a strong reputation for manufacturing reliable, high-quality boilers. Their products are designed to last and they deliver exceptional customer experience

• Price: Ideal boilers are often very competitive with their prices. That makes them popular with homeowners looking for quality and value for money

• After-sales support: Ideal boilers offer warranties from 2 to 12 years, depending on the individual model (as long as the boiler is installed by an Ideal Approved Installer and is registered within 30 days of installation)

Contact or pay a trade through Checkatrade and you’re covered by our 12-month guarantee of up to £1,000*

* Eligibility and T&Cs apply

Available grants for new boilers

The costs involved in replacing a boiler lead many homeowners to search for what government grants are available.

New boiler grants in England and Wales

The Boiler Upgrade Scheme offers grants to cover part of the cost of replacing fossil fuel heating systems with a heat pump or biomass boiler.

Available grants

• £7,500 towards an air source heat pump

• £7,500 towards a ground source heat pump (including water source heat pumps and those on shared ground loops)

• £5,000 towards biomass boiler costs

(Information correct at time of publishing, September 2024)

Eligibility

To be eligible, you must:

• Own the property you’re applying for

• Have installed (or plan to install) your new heating system on or after 1 April 2022

• Be replacing fossil fuel heating systems (such as oil, gas, or electric)

• Have a heating system with a maximum capacity of less than 45 kWh

You won't be able to get a grant if you're installing a hybrid heat pump system (e.g. a combination of a gas boiler and air source heat pump).

New boiler grants in Scotland

There are two options funded by the Scottish Government: The Warmer Homes Scotland Scheme and Home Energy Scotland Grant and Loan.

Grants and interest-free loans are available to eligible households to help with energy-saving home improvements.

Available grants

Grants and interest-free loans are available for several energy-saving measures, including central heating, loft and wall insulation, draught-proofing, and renewable systems for generating your own energy.

Eligibility

This scheme is available to homeowners and private sector tenants in Scotland who are struggling to pay for their energy and who have lived in their property for at least 12 months before applying for the grant.

New boiler grants in Northern Ireland

The Affordable Warmth Scheme (NI) helps low-income households and those in fuel poverty to make energy-efficiency improvements. This can include getting a new boiler fitted, subject to eligibility and assessment.

Summary

• A boiler normally lasts between 10-15 years before it needs replacing

• The cost of a new boiler will depend on the type, model, and manufacturer you choose alongside its performance, warranty, and size

• On average, expect to pay between £1,200 - £10,000 for a new boiler (supply only)

• Boiler installation costs are usually around £1,000 - £2,000

• In total, the average cost of a new boiler and installation is around £3,000 - £15,000

• Budget for additional costs such as new radiators and wifi-enabled thermostats for greater efficiency

• Changing your fuel type, switching one type of boiler for another, or moving your boiler's location can all impact the cost of a new boiler

• Popular boiler brands include Worcester Bosh, Vaillant, Ideal, Alpha, and Viessmann

• It's often possible to save on your new boiler cost through a government grant

• Always use an accredited engineer who is qualified to work safely with the type of boiler you choose

Get a quote for your new boiler

Comparing quotes from a selection of approved installers will help to ensure you get the best price for your new boiler.

Find and compare heating engineers we've checked and approved in your area on Checkatrade.

When you book your new boiler fitting with one of our tradespeople, we’ll guarantee their work up to £1,000*. Guaranteed for 12 months – Eligibility and T&Cs apply.

FAQs

How long is the warranty on a boiler?

Most good quality boilers come with warranties of between five and ten years.

How often do I need to get my boiler inspected?

Boilers should have an annual service, at the very least.

Should I replace my 10-year-old boiler?

The average lifespan of a modern boiler is around 10-15 years, if it's well-maintained. If your boiler is 10 years old and is still working well, then chances are you'll have a good few years left.

An annual boiler service will help make sure your boiler is in good working condition. Identifying and repairing small issues if/when they arise can add years to the life of your boiler.

However, if your boiler is constantly breaking down or needs major repairs, you might want to consider replacing it.

Are boilers expensive to replace?

Buying a new boiler is quite an investment for most people. You want to get it right.

The average new boiler cost is between £1,200 - £10,000. In addition, labour for the new boiler installation can cost around £1,000 - £2,000.

Given the cost of replacing a boiler, you should always weigh up the cost of boiler repair versus replacing your boiler with a new one.

Is replacing a boiler a big job?

Replacing a boiler is a fairly standard job for boiler engineers but it does usually take time. Depending on the complexity of the installation, it can take anywhere from 6 hours to 4 days. If you're changing the type of boiler in your home or moving the boiler, it will take longer to complete the job.

Will a new boiler make my house warmer?

That depends on your home and your old and new boilers. If you have an old boiler, it's likely that its efficiency isn't great – potentially less than 50%.

Inefficient boilers will struggle to heat your home well, especially if you live in a large property.

One of the biggest benefits of installing a new boiler is that it tends to be 90%+ efficient. So, installing a new boiler can make your house warmer and lower your energy bills at the same time.

What size boiler do I need?

The boiler size will depend on the size of your home. For example, a 1-bedroom flat will need a smaller boiler than a 3-bedroom house.

Generally speaking, you will need a 24kw to 30kw boiler in anything up to a 3-bed home. Larger homes will need something over 35kw, due to the number of radiators.

If you're installing an electric boiler then you will need 9kw to 12kw for the average home.

The simplest way to calculate the size of an electric boiler for your home is to times the number of radiators you have by 1.5 to give you the number of kW you need.

Speak to a certified local boiler installer for professional advice and guidance.

It's a choice between Vaillant, Baxi and Worcester Bosch, isn’t it?

Most plumbers and heating engineers will have their favourite brands, with Vaillant being seen as the mid-range go-to for many in the trade. Worcester Bosch is another favourite, although tends to be a little pricier in set-up costs and parts.

Baxi and Ideal boilers are other names you may see, although the Viessmann brand is gaining popularity and has good reviews of late.

The better-known the boiler brand, the easier it will be to find parts should something go wrong. You may wish to research brands or speak to a qualified heating engineer in your area.

Do I stick with a gas boiler or change to an electric boiler?

Electric boilers are becoming more popular as people see them as more environmentally friendly. And, they can be more fuel-efficient.

They provide heat and water in much the same way and usually need less maintenance (especially as they don’t have the potential to leak carbon monoxide).

Electric boilers work best in small-to-medium homes. But remember, electricity does tend to cost more than gas and fuel prices can vary.

What about biomass boilers?

Some people favour biomass boilers for being greener, but these are a larger investment than other boilers.

The average cost of a new biomass boiler plus installation is around £19,000. Talk to a central heating engineer in your area to discuss which boiler type is best for you.

Who are the best people to fit a boiler?

We would always recommend hiring an engineer certified to work with the type of boiler you choose. That's a Gas Safe Registered engineer for gas boilers, an OFTEC-registered technician for oil boilers, and a heating engineer qualified in both electrics and plumbing for electric boilers.

What are the benefits of a new boiler?

• Energy efficiency: A new boiler will produce more heat, heat water quicker and use less energy to do so

• Lower heating bills: Increased efficiency means lower energy bills, as your new boiler won't use as much energy

• Quieter home: Modern boilers are quieter than older models

• More space: New boilers are smaller and space-efficient so it frees up more cupboard space for you to utilise

• Accurate temperature control: New boilers are much more reliable than older ones at giving you the right temperature

• Better value for your property: Energy rating affects the value of a property and a new boiler will get you a better energy rating

What size boiler do you need?

When installing a new boiler, you must get the right size boiler for your home. Boilers in the UK are sized based on their output in kilowatts (kW), rather than their physical size.

As a general rule, the more heat you need for heating and/or hot water, the higher the boiler output you'll need.

One of the easiest ways to work out which size boiler you need is to count the number of radiators, bathrooms and bedrooms you have in your home:

For larger homes (4+ bedrooms and 3+ bathrooms), you'll most likely need a system or regular boiler to efficiently meet your heating needs.

Issues if your boiler is too big (oversized)

Big isn't always better when it comes to boilers, as having an oversized boiler can cause numerous issues, including:

• More power is needed to heat the same volume of water

• Wasted energy

• Higher energy bills

• Poor or unreliable performance

Problems if your boiler is too small (undersized)

Nobody wants to wake up to a cold house and freezing shower on a cold winter's morning. If your boiler is undersized for your home then you could be dealing with these issues:

• It won't be able to keep up with the heating demands of your home

• Lack of hot water

• Lack of heating

Thankfully, modern boilers are much more efficient than their predecessors so it's easier to work out the size of boiler that you need for your home.

If in doubt, speak to your local experienced boiler fitters for their professional advice and guidance on choosing the right size boiler.

*Guaranteed for 12 months – Eligibility and T&Cs apply.

More Cost Guides

Patio laying: Cost breakdown 2025

How much does it cost to retrofit a house in the UK?

External wall insulation: Cost breakdown 2025

View all

More Central Heating Articles

How much does a boiler service cost?

Cost of moving a boiler

Central heating installation cost guide

View all