New Boiler Installation Costs 2026 (Updated)

A straightforward combi replacement can start from £1,945 supplied and fitted, including VAT. Changing boiler type, replacing a hot-water cylinder or moving the appliance involves a different scope of work and can increase the total.

There are two useful figures when budgeting: an advertised starting price and a broader installation estimate. The starting price shows an available entry point; a guide estimate helps you prepare for other installation requirements.

Starting prices for boiler replacements

These examples are iHeat’s advertised starting prices, checked on 1 October 2026. They are not national averages or prices for replacing an entire heating system.

Wider installation budgets

For a separate full market reference, see the following supplied-and-installed estimates:

These are approximate third-party estimates, not fixed offers or iHeat customer averages. Their scope differs from the starting-price packages above. Confirm VAT and the precise inclusions when obtaining a quote.

A straightforward job can cost less than these guide figures. A complicated conversion or substantial additional work can cost more.

What do real boiler installations cost?

iHeat’s August 2026 installation data shows an average contract value of £2,820 including VAT. The middle half of values fell between approximately £2,525 and £3,247.

A basic combi swap may cost less, while an installation involving a different package or additional work may cost more.

Source: completed boiler orders included in sales, with August 2026 fitting dates. Figures are VAT-inclusive contract values, not a national average or a breakdown by installation type.

How does boiler type affect the price?

Combi boiler replacement

A combi heats water on demand without a separate hot-water cylinder. Replacing an existing combi in the same position usually involves fewer changes than converting from another system.

Starting packages can cost less than £2,000, but the suitable model depends on heating requirements, hot-water demand and the incoming water supply.

Pay attention to the exact model, output and warranty. A more expensive boiler is not automatically a better match for the property.

System boiler replacement

A system boiler works with a separate hot-water cylinder. The key pricing question is whether that cylinder stays.

If it remains suitable, the work may focus on replacing the boiler and its connections. A new cylinder adds equipment and labour, while changing its capacity or position can require further alterations.

Compare boiler-only replacement quotes separately from packages that include a cylinder.

Heat-only boiler replacement

Heat-only boilers, also called regular or conventional boilers, work with a separate cylinder and external heating-system components. Many installations also have water-storage tanks.

The price depends partly on which components remain serviceable. Ask the installer to identify anything that needs replacing alongside the boiler.

The Energy Saving Trust’s boiler guide explains the differences between combi boilers and systems that store hot water.

How much does converting to a combi cost?

Around £4,000 is a useful published guide figure for common conversions, although it is not a fixed price or a minimum. The relevant estimate depends on the starting system and the work included.

Regular or heat-only boiler to combi

This conversion replaces stored hot water with water heated on demand.

The work can include removing the cylinder and redundant tanks, reconnecting pipework and changing controls. A different boiler position or flue route may also be needed.

Before choosing a combi, have the incoming water supply and simultaneous hot-water demand assessed. Removing a cylinder frees space, but the replacement still needs to meet the household’s needs.

System boiler to combi

This removes the need for the hot-water cylinder and changes the associated pipework and controls.

Check whether cylinder removal is included and whether the new boiler will remain in the existing position. If it is moving, establish whether relocation is already included in the total.

Back boiler to combi

A back-boiler conversion needs an assessment of the existing appliance, its removal or decommissioning and the new boiler position.

Ask what happens to the fireplace opening afterwards. Plastering, decorating or replacing a fire may be outside the heating installation.

How much does moving a boiler cost?

Moving a boiler adds work to connect it in its new position. Check whether your replacement quote already includes the move before adding a separate allowance.

Some installers use fixed relocation charges. For example, iHeat’s replacement-pricing tariff uses these categories:

Named destinations use their own category. For example, selecting a loft/attic move uses the £795 tariff rather than the generic £895 another-floor category. Moving within the existing room uses the £495 charge.

These are relocation additions within a replacement quote, not prices for moving an existing boiler as a standalone job. The proposed position must still be suitable.

Three examples of how the total changes

1. Straightforward combi swap: £1,945

An existing combi is replaced in the same position using a suitable starting-price package.

Illustrative total: £1,945, assuming no separately priced work or optional upgrades.

2. Combi replacement with a same-room move: £2,440

The same package is selected, with the boiler moved elsewhere in the room.

Calculation: £1,945 + £495 relocation = £2,440.

This assumes the package and relocation category are suitable and no other extras are selected.

3. Conversion with additional finishing work: £4,300

Suppose a homeowner receives a £4,000 conversion quote including VAT, covering the boiler, agreed system alterations and removal of redundant equipment. They also receive a separate £300 quote including VAT for making good and decorating.

Their total project budget is £4,300.

This is a hypothetical budgeting example, not a customer installation or advertised package. Its purpose is to show why the heating quote and the cost of finishing the room may differ.

What additional costs should you allow for?

Only add an allowance where the work is required and excluded from the main quote. Controls, cleaning and other items may already be included.

For context, Which? publishes these guide figures:

These are third-party guide figures from Which?’s article dated September 2025, not current fixed installation add-ons. Confirm VAT, labour and materials before using them in a final budget. Source: Which? boiler installation costs.

A chemical flush and a power flush are different treatments. Ask which cleaning method is included rather than assuming a separately advertised power-flush price must be added.

Other work, such as difficult flue access, radiator replacement or repairs to existing pipework, needs an installation-specific assessment.

What should a complete boiler quote include?

Use this checklist to compare the same work across installers.

A supply-only appliance price is not comparable with a complete installation package.

A fixed quote should also explain what information it relies on and what could change the agreed scope. Clear photographs or a survey help establish the work before installation.

How can you tell whether a quote offers good value?

Compare suitable equipment and equivalent work, rather than judging the headline price alone.

If one quote is higher, ask what accounts for the difference. It may include a cylinder, more extensive pipework, different controls or finishing work.

If one is lower, check that required work has not been left out. A low price can still represent good value when the installation is straightforward and the package is complete.

Also consider warranty support and who will handle problems afterwards. These are part of the service you are buying.

Should you repair or replace the existing boiler?

A repair may be sensible when the fault is isolated, parts are available and the rest of the appliance is in reasonable condition.

Replacement becomes more attractive when breakdowns recur, several components need attention or parts are difficult to obtain.

Ask for a diagnosis and repair estimate. Age alone does not determine whether replacement is worthwhile, and potential energy savings should be assessed against the existing boiler and household usage.

What will the boiler cost after installation?

Allow for servicing as well as fuel bills. Follow the manufacturer’s maintenance requirements and keep the records needed for the warranty.

Running costs depend on insulation, heating demand, controls and how the system is used. Improved efficiency can reduce fuel use, but advertised savings are not guaranteed for every home.

If using finance, compare the deposit, APR, repayment term and total amount payable. A lower monthly payment can simply spread the cost over a longer period.