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Cost, read every week

New boiler cost in the UK

What a gas boiler replacement costs fitted, from the prices named installers publish on their own sites: a 25 or 30 kW combi, or a system boiler, each swapped like for like. Every price shows its type and the date we read it.

Sellers read
3
Last read
01/11/2026
Specs
3
Prices this week
3

01Prices

Every seller's latest price, spec by spec

Each spec is compared on its own, sorted by price, then by the date we read it. One price type and grant state is compared; any other sits apart and says so.

Combi boiler swap, 25 kW

Its own page, with the index

Some seller links may earn FittedPrice a commission. It never changes the order: every list is sorted by price, then by the date we read it. How we make money

Combi boiler swap, 25 kW: every seller's latest price
SellerPriceTypeIncludesReadLink
01BOXTIdeal Logic Combi 24kW£1,760FromNo grantIncludesNot stated Read today, 01/11/2026Seller site
Shown apart: other price types, other grant states and prices not checked recently. Not compared with from prices
iHeatWorcester Bosch 2000 25kW£2,295TypicalNo grantIncludesFlue: Through a wall, Note: example installed price, Position: existing, Replacing: Combi boiler Read today, 01/11/2026Seller site

Read from 2 sellers on 01/11/2026. How we read prices

Combi boiler swap, 30 kW

Its own page, with the index

Some seller links may earn FittedPrice a commission. It never changes the order: every list is sorted by price, then by the date we read it. How we make money

Combi boiler swap, 30 kW: every seller's latest price
SellerPriceTypeIncludesReadLink
01Worcester BoschWorcester Bosch Greenstar 1000 30kW£2,550TypicalNo grantIncludesNote: indicative price inc. VAT and installation, Package: FastTrack Read today, 01/11/2026Seller site

Read from 1 seller on 01/11/2026. How we read prices

System boiler swap

Its own page, with the index

Not checked yet

We have not read a price for this spec from any seller yet, so there is no figure here. Each price will show with its type, grant state and the date we read it.

02Grants

Grants by nation

England, Wales, Scotland and Northern Ireland run different schemes. Each grant links to the official page we checked it on.

England
Wales
Scotland
Northern Ireland
None of the grants we track pays towards a new boiler here.

03Like for like

What counts, and what is kept apart

A seller's price is matched to a spec by its stated size and scope, never by price.

Sellers' from prices are for their smallest combi swapped in the same place, so this page leads with the 25 kW combi swap. A bigger combi and a system boiler each have their own comparison on this page.

Every price here is the boiler fitted: a swap in the same place with a standard flue. Moving the boiler, converting a system or back boiler to a combi, or fitting a new cylinder is a different job, priced after a survey, so it is kept off these comparisons.

Flush, magnetic filter, thermostat and warranty are recorded when the seller lists them, and shown on each row, but a price counts without them.

Some seller links may earn FittedPrice a commission. It never changes the order: every list is sorted by price, then by the date we read it. How we make money

Illustration of a wall-hung combi gas boiler with its pipework
Fig. 1Combi boilerCombi boiler swap, 25 kW

04Questions

New boiler: questions

How much does a new boiler cost in the UK?
Combi boiler swap, 25 kW, read 01/11/2026: BOXT from £1,760; iHeat £2,295 typical. Fewer than three sellers share one price type, so no median yet. Combi boiler swap, 30 kW, read 01/11/2026: Worcester Bosch £2,550 typical. One seller so far, so no median yet. System boiler swap: not checked yet.
How much does a combi boiler replacement cost?
Combi boiler swap, 25 kW, read 01/11/2026: BOXT from £1,760; iHeat £2,295 typical. Fewer than three sellers share one price type, so no median yet. Combi boiler swap, 30 kW, read 01/11/2026: Worcester Bosch £2,550 typical. One seller so far, so no median yet. Both are a combi replacing a combi in the same place with a standard flue; the 30 kW spec is the next size up. A boiler moved to another room or a system converted to a combi is a different job, kept off these comparisons.
Why are some prices "from" and others "typical"?
A from price is the seller's advertised starting price; a fixed price is a set price published for that job; a typical price is the seller's own published typical or example price. They are different things, so each is shown with its type and only prices of one type are compared.
Which seller is cheapest for a new boiler?
Combi boiler swap, 25 kW: we cannot call any seller cheapest yet. Only BOXT has a from price read in the last 14 days, and we only compare prices of one type.
Is there a grant for a new boiler?
Energy Company Obligation (ECO4) (pays for agreed work): England, Scotland and Wales only. Northern Ireland: none of the grants we track. Each grant page says who qualifies, checked on the official page.
How are these prices read?
From each seller's own website, once a week, with the date we read it. Every price says its type (from, fixed or typical) and whether a grant has been taken off. Commission never changes the order, and we never arrange finance.

05Sources

Where these figures come from

  1. BOXTread 01/11/2026
  2. iHeatread 01/11/2026
  3. Worcester Boschread 01/11/2026
  4. Energy Company Obligation (ECO4)checked 31/10/2026
  5. How we read prices

By FittedPrice Studio. Prices read at source on each seller's own site, each with the date we read it. Editorial policy. Updated 01/11/2026