How Much Does a New Boiler Cost in 2026?

A new boiler is one of the most common — and most dreaded — household expenses. When your boiler breaks down in the middle of winter, the cost of replacement suddenly becomes very real. But even if your boiler is still working, replacing an old, inefficient model can save you hundreds of pounds a year on energy bills and provide more reliable heating and hot water.

This guide covers the full cost of installing a new boiler in the UK in 2026, including combi, system, and conventional boilers, brand comparisons, available grants, Gas Safe regulations, and what to expect during installation. Whether you are a homeowner planning a replacement or a heating engineer pricing up a job, these figures reflect current market rates.

New Boiler Cost Summary

Here is a quick overview of what a new boiler costs in 2026, fully installed. These prices include the boiler unit, standard flue, basic controls (room thermostat and programmer), installation labour, system flush, and building regulations notification. They are for a straightforward like-for-like replacement in the same location.

Boiler Type	Installed Cost	Best For
Combi Boiler	£1,500 – £3,500	1–3 bed, 1 bathroom
System Boiler	£2,000 – £4,000	3–4 bed, 2+ bathrooms
Conventional Boiler	£2,000 – £4,500	Large houses, high demand

If the boiler is being moved to a new location or you are converting from one boiler type to another (for example, conventional to combi), expect to add £500 to £1,500 to these prices for the additional pipework and modifications required.

Combi Boiler: £1,500 – £3,500 Installed

A combi (combination) boiler provides both central heating and instant hot water from a single unit, without the need for a separate hot water cylinder or cold water storage tank. Combi boilers are the most popular choice in the UK, accounting for over 70 percent of all new boiler installations.

Advantages:

• Compact — no need for a hot water cylinder or header tank, freeing up cupboard and loft space
• Hot water on demand — no waiting for a cylinder to heat up
• Energy efficient — only heats water when you need it, no standing heat losses from a stored cylinder
• Cheaper to install than system or conventional boilers (less pipework and fewer components)
• Simpler system with fewer potential points of failure

Limitations:

• Flow rate is limited — typically 10 to 15 litres per minute. If you run two showers simultaneously, both will have reduced water pressure
• Not ideal for large houses with multiple bathrooms running at the same time
• Dependent on mains water pressure — if your mains pressure is low, the hot water flow rate will be poor

Best for: Flats, 1 to 3 bed houses with one bathroom, and properties where space is limited. If you have good mains water pressure and do not need to run multiple hot water outlets simultaneously, a combi boiler is usually the best choice.

System Boiler: £2,000 – £4,000 Installed

A system boiler works with a sealed hot water cylinder (usually stored in an airing cupboard) but does not require a cold water storage tank in the loft. The boiler heats the water and stores it in the cylinder, ready for use. Most of the major heating components — the pump, expansion vessel, and diverter valve — are built into the boiler, making installation simpler than a conventional boiler.

Advantages:

• Can supply multiple hot water outlets simultaneously without a drop in pressure
• Compatible with solar thermal panels for supplementary water heating
• Stronger hot water flow than a combi boiler, especially with an unvented cylinder
• No cold water tank needed in the loft

Limitations:

• Requires space for a hot water cylinder (typically in an airing cupboard)
• Hot water can run out if the cylinder is emptied — you need to wait for it to reheat
• Slightly higher installation cost than a combi boiler

Best for: 3 to 4 bed houses with two or more bathrooms, and households with high hot water demand. If you regularly need hot water at multiple outlets simultaneously (such as two showers and a bath running at the same time), a system boiler with an appropriately sized cylinder is the right choice.

The cost of the hot water cylinder is included in the prices above for a like-for-like replacement. A new unvented cylinder on its own costs £500 to £1,200 supplied and installed, depending on the size and brand.

Conventional Boiler: £2,000 – £4,500 Installed

A conventional (regular or heat-only) boiler works with both a hot water cylinder and a cold water storage tank (typically in the loft) plus a feed and expansion tank. It is the oldest type of central heating system and is still found in many older properties. While less common in new installations, conventional boilers remain the best option for very large properties with high hot water demand.

Advantages:

• Can supply very high hot water demand — ideal for large houses with multiple bathrooms
• Compatible with solar thermal panels
• Works well with older heating systems and gravity-fed pipework
• Replacement is straightforward if you already have a conventional system

Limitations:

• Requires the most space — a hot water cylinder, cold water tank, and feed and expansion tank
• Less energy efficient than a combi or system boiler due to standing heat losses from the cylinder
• Hot water is not instant — the cylinder needs time to heat up
• Cold water tank in the loft can freeze in very cold weather if not properly insulated

Best for: Large houses (4+ bedrooms) with three or more bathrooms, properties with existing conventional systems that are being replaced like-for-like, and houses where mains water pressure is too low for a combi or unvented system boiler.

Boiler Brands Compared

The brand of boiler you choose affects both the upfront cost and the long-term reliability. Here is how the major brands compare in 2026.

Brand	Combi Price (unit only)	Warranty	Tier
Worcester Bosch	£900 – £1,800	Up to 12 years	Premium
Vaillant	£850 – £1,700	Up to 10 years	Premium
Viessmann	£900 – £1,600	Up to 12 years	Premium
Baxi	£600 – £1,200	Up to 10 years	Mid-range
Ideal	£550 – £1,100	Up to 12 years	Mid-range
Alpha	£500 – £900	Up to 7 years	Budget
Glow-worm	£500 – £950	Up to 7 years	Budget

Worcester Bosch consistently tops reliability surveys and is the most recommended brand by Gas Safe engineers in the UK. The Greenstar range is the flagship, with the Greenstar 4000 and 8000 being the most popular models. Worcester Bosch offers up to 12 years warranty when installed by an accredited installer.

Vaillant is a German manufacturer with an excellent reputation for quality and efficiency. The ecoTEC range is extremely popular in the UK, particularly the ecoTEC Plus and ecoTEC Exclusive models. Vaillant boilers tend to be very quiet and energy efficient.

Viessmann is another German brand that has gained significant market share in the UK. The Vitodens range is known for its build quality, compact design, and excellent efficiency ratings. Viessmann offers up to 12 years warranty on selected models.

Baxi is a British brand with a long history in the UK heating market. The 800 series offers good reliability at a competitive price. Baxi boilers are popular with installers due to their straightforward installation and readily available parts.

Ideal is another established British brand. The Logic and Vogue ranges are well-regarded for reliability and value. Ideal offers up to 12 years warranty on the Vogue Max range, which is competitive with the premium brands at a lower price point.

Additional Costs to Consider

The headline installation cost covers a straightforward like-for-like replacement. But several factors can add to the total cost.

Moving the Boiler: £500 – £1,500

If you want to move the boiler to a different location — for example, from a kitchen to a utility room or from downstairs to upstairs — the additional pipework, flue routing, and making good will add £500 to £1,500 to the cost. Moving the boiler to a significantly different location (such as from one end of the house to the other) can cost even more.

System Conversion: £500 – £1,500

Converting from a conventional system to a combi boiler involves removing the hot water cylinder and the cold water and expansion tanks in the loft, as well as re-routing pipework. This typically adds £500 to £1,500 to the cost of the boiler installation. However, you gain significant space and benefit from instant hot water.

Power Flush: £300 – £600

A power flush cleans the entire central heating system — pipework, radiators, and boiler — by circulating a chemical cleaning solution at high velocity. This removes sludge, rust, and debris that accumulates over time and reduces the efficiency of the system. Many boiler manufacturers require a system flush as a condition of the warranty. A power flush costs £300 to £600 depending on the number of radiators and the extent of contamination.

Smart Controls: £150 – £400

Modern smart heating controls such as Nest, Hive, or the Worcester Bosch Wave allow you to control your heating remotely via a smartphone app. They learn your schedule, adjust to the weather, and can reduce energy bills by 10 to 15 percent. The cost includes the thermostat unit and installation — some boiler brands include basic smart controls in the installation price.

Magnetic Filter: £100 – £200

A magnetic filter (such as a MagnaClean) is fitted to the return pipe near the boiler and captures magnetic sludge and debris before it enters the boiler. This protects the boiler's heat exchanger and improves efficiency. Most installers now fit a magnetic filter as standard, and many boiler warranties require one.

Radiator Upgrades: £100 – £300 per radiator

If your radiators are old and undersized, replacing them at the same time as the boiler makes sense. A new panel radiator costs £100 to £300 supplied and fitted, depending on the size. Thermostatic radiator valves (TRVs) cost £15 to £30 each fitted and are a requirement under building regulations for new boiler installations.

Boiler Grants and Funding

Several government schemes can help with the cost of a new boiler or heating system in 2026.

Boiler Upgrade Scheme (BUS): This scheme offers grants towards the cost of replacing a fossil fuel heating system with a low-carbon alternative. As of 2026, the grant is up to £7,500 for an air source heat pump and up to £5,000 for a ground source heat pump. The scheme does not cover like-for-like gas boiler replacements — it is specifically for switching to renewable heating.

ECO4 (Energy Company Obligation): The ECO4 scheme requires large energy suppliers to fund energy efficiency improvements in low-income and vulnerable households. This can include boiler replacement for qualifying households. To be eligible, you typically need to be receiving certain benefits (such as Universal Credit, Pension Credit, or Child Tax Credits) and your property must have a low EPC rating (D, E, F, or G). Contact your energy supplier or the Simple Energy Advice helpline (0800 444 202) to check eligibility.

Local authority grants: Some local councils offer grants or interest-free loans for boiler replacements, particularly for elderly or vulnerable residents. Check with your local council's housing or environmental health department.

Manufacturer finance: Several boiler brands offer 0% finance over 2 to 5 years through their installer networks. This spreads the cost of a new boiler into manageable monthly payments. Worcester Bosch, Vaillant, and Ideal all offer finance options through accredited installers.

Gas Safe Requirements

By law, all gas work in the UK — including boiler installation, servicing, and repair — must be carried out by a Gas Safe registered engineer. It is illegal for an unregistered person to carry out gas work, and doing so puts lives at risk from carbon monoxide poisoning, gas leaks, and explosions.

How to check: Every Gas Safe registered engineer carries an ID card with a unique registration number, a photo, and an expiry date. You can verify their registration on the Gas Safe Register website (gassaferegister.co.uk) or by calling 0800 408 5500. The card also shows which types of gas work the engineer is qualified to carry out — make sure boiler installation is listed.

After installation: The installer must notify the local building control department that the work has been completed. Gas Safe registered engineers can self-certify the work, and you should receive a Building Regulations Compliance Certificate within a few weeks of the installation. The installer must also leave you with a benchmark commissioning checklist, which records the settings and performance of the new boiler. This document is essential for warranty claims.

Annual servicing: A new boiler should be serviced annually to maintain the warranty and ensure safe operation. An annual boiler service costs £60 to £100 and should be carried out by a Gas Safe registered engineer. Many boiler warranties are invalidated if the boiler is not serviced annually.

How Long Does Boiler Installation Take?

Like-for-like replacement (same location, same type): 1 day. The engineer will drain the system, remove the old boiler, fit the new boiler, connect the pipework and flue, fill and pressurise the system, commission the boiler, and test all controls.

Boiler relocation: 2 to 3 days. Additional time is needed to run new gas, water, and heating pipework to the new location, install a new flue route, and make good the old boiler position.

System conversion (e.g., conventional to combi): 2 to 3 days. This involves removing the old boiler, cylinder, and tanks, re-routing pipework, installing the new combi boiler, and commissioning the system.

Full heating system (new boiler + all new radiators): 3 to 5 days depending on the number of radiators and the complexity of the pipework.

If you are a heating engineer quoting for boiler installations, including a clear timeline in your proposal helps the homeowner plan around the disruption. Our scope of work guide covers how to structure this effectively, and our quote calculator can help you price the job competitively.

Tips for Getting Boiler Installation Quotes

Get at least three quotes. Boiler installation prices vary significantly between installers. Getting three detailed quotes allows you to compare the boiler model, warranty, installation scope, and price. Be wary of quotes that seem unusually low — they may be using a budget boiler, cutting corners on the flush or controls, or not including a magnetic filter.

Check the warranty terms. The length of the warranty is important, but so are the conditions. Many manufacturers require annual servicing by a Gas Safe registered engineer, a system flush at installation, and a magnetic filter. If these conditions are not met, the warranty may be invalidated. Check what is required before you commit.

Ask about the full specification. A comprehensive quote should include the boiler make, model, and output (kW), the flue type and route, the controls (thermostat, programmer, TRVs), whether a system flush is included, whether a magnetic filter is included, the warranty length and conditions, and the estimated installation time.

Consider efficiency. Modern condensing boilers are rated at 90 to 94 percent efficiency, compared to 60 to 80 percent for older non-condensing models. The difference can save £200 to £400 per year on gas bills. When comparing quotes, consider the long-term running costs as well as the upfront installation cost.

Check Gas Safe registration. This is non-negotiable. Verify every engineer's Gas Safe registration before allowing them to quote, let alone work on your heating system. An unregistered installer cannot legally install a boiler, and their work will not be covered by building regulations or manufacturer warranties.

Frequently Asked Questions

How much does a new boiler cost in the UK in 2026?

A new boiler in the UK in 2026 costs between £1,500 and £4,500 fully installed, depending on the type and brand. A combi boiler costs £1,500 to £3,500, a system boiler costs £2,000 to £4,000, and a conventional boiler costs £2,000 to £4,500. These prices include the boiler, installation labour, flue, controls, and building regulations notification.

Which boiler brand is best in the UK?

Worcester Bosch and Vaillant are consistently rated as the best boiler brands in the UK for reliability and efficiency. Viessmann is another premium brand with excellent build quality. Baxi and Ideal are good mid-range options that offer solid reliability at a lower price point. Alpha and Glow-worm are budget-friendly brands that still perform well. The best brand for you depends on your budget, property size, and hot water demand.

Can I get a free boiler or a boiler grant?

The UK government's Boiler Upgrade Scheme offers grants of up to £7,500 towards the cost of a heat pump installation. For gas boiler replacements, the ECO4 scheme provides funding for low-income households and those receiving certain benefits. Some energy suppliers also offer boiler replacement schemes. Eligibility depends on your circumstances, property type, and the existing heating system.

How long does it take to install a new boiler?

A straightforward like-for-like boiler replacement typically takes 1 day. If the boiler is being moved to a new location, the installation usually takes 2 to 3 days due to the additional pipework and flue routing required. Converting from a conventional system to a combi boiler takes 2 to 3 days as it involves removing the hot water cylinder and header tank and re-routing the pipework.