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By Emily Rivers
Last updated 18th August 2026

Cost to fit a new combi or system boilers

Replacing your old boiler with a new model has never been easier. Manufacturers are offering long warranties up to 10 year, even on cheaper models and there are plently of gas safe engineers willing to help with the installation.

Home boiler prices range from £700 to £5,000 and take from 1 to 3 days to install depending on your setup. The cheapest installation price is around £1,600 but expect to pay on average around £2,000 to £3,000 in total. 

Cost of a new boiler installation in the UK

Install a new boiler cost

Boiler installation hidden costs

Modern boilers are very efficient and easy to install for qualified gas safe engineers but removing your old system might create additional costs that you did not envisage. 

  • Powerflushing the existing system using the old boiler to clean out corrosion debris might be a prerequisite of the heating engineer or new boiler manufacturer warranty. The existing radiators and pipes will have corrosion debris in them which needs to be cleaned out so it doesn’t clog up the highly efficient heat exchanger in your new boiler. Expect to pay between £300 to £800.
  • Removing the old boiler - Your old boiler may have been bigger (new boilers are very compact), and had pipes running in different directions. So you might need to make good cabinets or walls before or after installing the new boiler. Painter & decorators or carpenters may be required.
  • New location or configuration of boiler -  A boiler swap, usually a like for like combi boiler, is the easiest and cheapest installation with little pipework modifications required. For different boiler configurations the gas safe engineer will be required to adapt pipework and fit the new flue to suit the boiler. If you are changing the boiler location you may also need re-route the gas pipe that feeds it and power supply to control it. Keep cost down by choosing a boiler that is easy to swap.
  • Fitting the new boiler - The engineer needs to make all the connections including, power supply, gas, mains water in, flow and return pipes, hot water out, flue, pressure relief pipe. Extras offered to customers include, corrosion debris filters, adding limescale inhibitor and system corrosion inhibitor. The boiler manufacturers warranty might depend on some of these extras.
  • Replacing Gravity fed (open) system - If you replace with a combi or system boiler you will need to remove the old hot water tank and the expansion tanks in the loft. The engineer will be happy to take away the copper hot water tank and copper piping because they have value but might be more reluctant to remove the expansion tanks in the loft. If you want these removed make it clear to the engineer who will probably add it to his quote.
  • Smart heating controls - Most modern boilers can be controlled by smart heating controls so it would seem a good idea to upgrade on installation. They cost between £100 and £200 and take a couple of hours to install.
  • Register new boiler - The engineer should register your new boiler installation on the Gas Safe Register and also activate your manufacturers warranty with the supplier.

 

Extra costs to consider when getting a new boiler

Replace radiators £160-320
Add radiators £260-380
Powerflush radiators and pipes £250-800
Fit water tanks £135-180
Fit new central heating pipework £750-1,100
Install thermostat controls £120-250

How much do Combi boilers cost?

Image Name Cost
Glow-Worm Compact 28kW Combi Boiler Glow-Worm Compact 28kW Combi Boiler£643.19
Worcester Bosch Greenstar 2000 25kW Combi Gas Boiler Worcester Bosch Greenstar 2000 25kW Combi Gas Boiler£881.80
Glow-Worm Energy 30C Erp Combi Boiler Glow-Worm Energy 30C Erp Combi Boiler£1005.59
Baxi 630 Combi 2 Boiler Baxi 630 Combi 2 Boiler£1036.79
Ideal Logic2 Max C24 24kW Combination Boiler Ideal Logic2 Max C24 24kW Combination Boiler£1166.03
Worcester Bosch Greenstar 8000+ Worcester Bosch Greenstar 8000+£1662.32
Vaillant ecoTEC Plus 836 36kW Combi Boiler Vaillant ecoTEC Plus 836 36kW Combi Boiler£1754.99
Vaillant EcoTEC Plus 840 40kW Combi Boiler Vaillant EcoTEC Plus 840 40kW Combi Boiler£1972.79
Viessman Vitodens 200-W 32kw Viessman Vitodens 200-W 32kw£1988.16
Worcester Bosch Greenstar 8000+ 45kW Combi Boiler Worcester Bosch Greenstar 8000+ 45kW Combi Boiler£2321.99

What are combi boilers?

Combi boilers (combination boilers) are compact small boilers which both heat water directly which comes out of your hot taps and also send hot central heating water to your radiators to heat your home.

How do combi boilers work?

To get your radiators hot the system water in your home's radiators and pipes is circulated using a pump through the combi boiler’s main heat exchanger which is heated by a gas burner.

When you turn on a hot water tap or shower a flow sensor tells the combi boiler’s diverter valve to redirect the heated system water internally through a second ‘plate to plate’ heat exchanger which indirectly heats up mains water and in seconds sends the now hot mains water to your hot tap or shower.

Why are combi boilers so popular?

No space needed for hot water cylinders or water tanks, low cost, range of out-puts to suit all properties, simple to install, maintain - all persuasive reasons why combi boilers are the number one choice when UK homeowners buy a new boiler.

Worcester Bosch combi boilers

  • Greenstar 2000 Combi boiler (25/30kw) - Suitable for one bathroom small to medium homes, fits between standard kitchen cabinets. Quietest in range, efficient and guarantee ranging from 5 – 6 years.
  • Greenstar 4000 Combi boiler (25/30kw) - Ideal for small to medium homes with one bathroom. Modern design, easy to use colour display, efficient, quiet and guarantee ranging from 7 - 8 years.
  • Greenstar Si Compact Combi boiler (25/30kw) - Suitable for small to medium homes with one bathroom, fits into a standard kitchen cupboard, easy to use controls and guarantee ranging from 7 – 8 years.
  • Greenstar CDi Compact combi boiler (28/32/36kw) - suitable for small, medium and large-sized properties with one or two bathrooms. Compact enough to fit into a standard kitchen cupboard but powerful enough for homes with more than one bathroom. Guarantee ranging from 7 - 8 years.
  • Greenstar 8000 Life Combi boiler (30/35/40/45/50kw) - most powerful wall hung combi boiler range with a modern design, wireless connectivity and guarantee ranging from 8 – 10 years.
  • Greenstar 8000 Style Combi boiler (30/35/40/45/50kw) - Top of the range, look like huge black or white wall hung iPhones, connected technology and power to comfortably heat large homes with two or more bathrooms. Guarantee ranging from 8 – 10 years.

Vaillant combi boilers

  • ecoFIT pure combi (25/30/35kw) - compact to fit in a cupboard so suitable for small homes. Efficient, quiet, smart controls and guarantee ranging from 2-10 years.
  • ecoTEC pro combi (24/28/30kw) - smart boiler for small to medium homes. Full range of thermostat controls (from analogue timers to ySMART app controlled) and 2-10 years guarantee.
  • ecoTEC plus combi (25/32/35/38kw) - high performance, precision control and efficiency suitable for any home and 5-10 years guarantee.
  • ecoTEC Green iQ combi (35/43kw) - best in range for efficiency and control, fully compatible with vSMART app, 85% recyclable and 5-10 years guarantee.

How much do system boilers cost

Image Name Cost
Glow-Worm Energy 30S System Boiler Glow-Worm Energy 30S System Boiler£1210.79
Vaillant ECOTEC PLUS 630 System Boiler Vaillant ECOTEC PLUS 630 System Boiler£1664.50
Worcester Bosch Greenstar 8000+ 35kW Gas System Boiler Worcester Bosch Greenstar 8000+ 35kW Gas System Boiler£1791.32
Viessmann Vitodens 200-W Viessmann Vitodens 200-W£1988.16

What are system boilers and how do they work?

System boilers are a great solution for large family homes as they provide a constant supply of hot water for baths, showers and washing up. A system boiler works by filling a large, insulated storage cylinder with hot water so there is a constant supply of hot water ready to be used at any time.

Worcester Bosch system boilers

  • Greenstar 4000 System boiler (12/15/18/21/24kw) - Suitable for one bathroom small to medium homes. Modern design, quiet, easy to use colour display and guarantee ranging from 7 – 8 years.
  • Greenstar I System boiler (27/30kw) - Small but powerful, suitable for small, medium and large homes whilst fitting into a standard kitchen cupboard, easy to use controls and guarantee ranging from 7 – 8 years.
  • Greenstar 8000 Life System boiler (30/35kw) - most powerful wall hung system boiler range with a modern design, wireless connectivity and guarantee ranging from 8 – 10 years.
  • Greenstar 8000 Style System boiler (30/35kw) - Top of the range, look like huge black or white wall hung iPhones, connected technology and power to comfortably heat large homes with two or more bathrooms. Guarantee ranging from 8 – 10 years.

Vaillant system boilers

  • ecoFIT pure system (12/15/18/25/30kw) - compact to fit in a cupboard so suitable for small homes. Efficient, quiet, smart controls and 2-10 years guarantee.
  • ecoTEC plus system (12/15/18/24/30/37kw) - high performance, precision control and efficiency suitable for any home and 5-10 years guarantee.
  • ecoTEC Green iQ system (27kw) - best in range for efficiency and control, fully compatible with vSMART app, 85% recyclable and 5-10 years guarantee.

Conventional boilers

Image Name Cost
Glow-worm Easicom 3 25kW Boiler Glow-worm Easicom 3 25kW Boiler£618.00
Vaillant ecoFIT Pure 412 Boiler Vaillant ecoFIT Pure 412 Boiler£990.00
VAILLANT ECOTFIT PURE REGULAR VAILLANT ECOTFIT PURE REGULAR£1192.00
Vaillant ecoTEC Plus 424 boiler 24kW Vaillant ecoTEC Plus 424 boiler 24kW£1381.00
Worcester Bosch Greenstar 8000+ 35kW Boiler Worcester Bosch Greenstar 8000+ 35kW Boiler£2007.00
Keston Heat 2 55kW Boiler Keston Heat 2 55kW Boiler£2701.00

 


Estimates for common heating engineer jobs;

JobEstimate
Cost to replace a hot water immersion heater£298
Cost to fit underfloor heating£1,228
Cost to service a gas fire£150
Cost to replace a vented hot water cylinder£586
Cost to replace a central heating pump£222
Cost to replace a heating programmer£255
Cost to power flush central heating systems£603 Visit
Cost to install heating oil storage tank£2,160
Cost to replace an oil boiler£3,228
New combi or system boiler installation – like for like replacement£2,718
Cost to move and relocate a boiler£830
Complete gas safety certificate for one gas appliance£90
Cost to install heated skirting boards£2,200
Cost to install an LPG boiler£2,026
Cost to install hydrogen boiler£1,350
Cost to install a gas fire£1,059
Cost to install a chimney liner£761
Cost to install biomass boiler£5,705
Cost to install a ground source heat pump£13,563
Cost to fix a boiler fault error code£85
Cost to install an unvented hot water cylinder£3,669
Cost to fit thermostatic radiator valves (TRVs)£111
Cost to fit smart heating controls£235
Cost to fit a magnetic filter for boiler£155
Cost to fit a heated towel rail£119
Cost to fit a radiator£184
Cost to install a gas cooker or hob£202
Boiler service cost£100
Boiler repair cost for pump, diverter valve or heat exchanger£233
Cheap boiler insurance£20 per month
Cost to install an air source heat pump£6,167
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Rates for other trades

Install a new boiler cost in the UK
Estimate Install a new boiler cost in the UK, including Combi Boiler valued at £643, based on hourly/daily rate (excluding VAT or callout charges)
Location in UKInstall a new boiler cost
Install a new boiler near London£1,649
Install a new boiler near Birmingham£1,517
Install a new boiler near Glasgow£1,599
Install a new boiler near Leeds£1,505
Install a new boiler near Liverpool£1,517
Install a new boiler near Sheffield£1,535
Install a new boiler near Edinburgh£1,577
Install a new boiler near Manchester£1,549
Install a new boiler near Belfast£1,475
Install a new boiler near Bristol£1,581
Install a new boiler near Leicester£1,511
Install a new boiler near Cardiff£1,535
Install a new boiler near Coventry£1,529
Install a new boiler near Bradford£1,523
Install a new boiler near Nottingham£1,529
Install a new boiler near Newcastle Upon Tyne£1,589
Install a new boiler near Brighton and Hove£1,567
Install a new boiler near Derby£1,533
Install a new boiler near Hull£1,481
Install a new boiler near Plymouth£1,511
Install a new boiler near Stoke-on-Trent£1,523
Install a new boiler near Southampton£1,585
Install a new boiler near Northampton£1,601
Install a new boiler near Wolverhampton£1,525
Install a new boiler near Luton£1,633
Install a new boiler near Portsmouth£1,585
Install a new boiler near Reading£1,671
Install a new boiler near Norwich£1,537
Install a new boiler near Milton Keynes£1,607
Install a new boiler near Bournemouth£1,583
Install a new boiler near Aberdeen£1,623
Install a new boiler near Peterborough£1,617
Install a new boiler near Bolton£1,523
Install a new boiler near Swindon£1,639
Install a new boiler near Southend-on-Sea£1,569
Install a new boiler near Warrington£1,533
Install a new boiler near Oxford£1,619
Install a new boiler near Swansea£1,531
Install a new boiler near Sunderland£1,589
Install a new boiler near Slough£1,683
Install a new boiler near Kingswood£1,575
Install a new boiler near Telford£1,529
Install a new boiler near Cambridge£1,619
Install a new boiler near Ipswich£1,695
Install a new boiler near Blackpool£1,545
Install a new boiler near Middlesbrough£1,547
Install a new boiler near Dundee£1,597
Install a new boiler near Huddersfield£1,515
Install a new boiler near York£1,519
Install a new boiler near Poole£1,603
Install a new boiler near Watford£1,633
Install a new boiler near Newport£1,505
Install a new boiler near Colchester£1,611
Install a new boiler near Exeter£1,525
Install a new boiler near Blackburn£1,563
Install a new boiler near Crawley£1,617
Install a new boiler near Gloucester£1,611
Install a new boiler near Stockport£1,551
Install a new boiler near Basingstoke£1,643
Install a new boiler near Basildon£1,545
Install a new boiler near Cheltenham£1,609
Install a new boiler near Gateshead£1,593
Install a new boiler near Worthing£1,597
Install a new boiler near Rochdale£1,521
Install a new boiler near Oldham£1,525
Install a new boiler near Chelmsford£1,573
Install a new boiler near Birkenhead£1,519
Install a new boiler near Maidstone£1,561
Install a new boiler near Gillingham£1,547
Install a new boiler near Salford£1,547
Install a new boiler near Solihull£1,517
Install a new boiler near St Helens£1,567
Install a new boiler near Worcester£1,539
Install a new boiler near Lincoln£1,663
Install a new boiler near West Bromwich£1,519
Install a new boiler near Eastbourne£1,491
Install a new boiler near Wakefield£1,521
Install a new boiler near Wythenshawe£1,559
Install a new boiler near Bedford£1,609
Install a new boiler near Hemel Hempstead£1,631
Install a new boiler near Preston£1,557
Install a new boiler near Stevenage£1,617
Install a new boiler near Southport£1,499
Install a new boiler near Bath£1,563
Install a new boiler near Harlow£1,595
Install a new boiler near Sutton Coldfield£1,513
Install a new boiler near Darlington£1,559
Install a new boiler near Chester£1,547
Install a new boiler near Hastings£1,517
Install a new boiler near Nuneaton£1,491
Install a new boiler near Halifax£1,519
Install a new boiler near Hartlepool£1,525
Install a new boiler near Aylesbury£1,663
Install a new boiler near Doncaster£1,539
Install a new boiler near Grimsby£1,497
Install a new boiler near Wallasey£1,517
Install a new boiler near Londonderry£1,339
Install a new boiler near Stockton-on-Tees£1,543
Install a new boiler near Weston-super-Mare£1,521
Install a new boiler near High Wycombe£1,691
Install a new boiler near Ashford£1,539
Install a new boiler near Redditch£1,565
Install a new boiler near Wigan£1,537
Install a new boiler near Scunthorpe£1,469
Install a new boiler near Bury£1,513
Install a new boiler near Paisley£1,611
Install a new boiler near Bracknell£1,629
Install a new boiler near Burnley£1,503
Install a new boiler near Rugby£1,621
Install a new boiler near Guildford£1,675
Install a new boiler near Carlisle£1,529
Install a new boiler near Chatham£1,549
Install a new boiler near East Kilbride£1,595
Install a new boiler near Newcastle-under-Lyme£1,519
Install a new boiler near Chesterfield£1,521
Install a new boiler near Burton upon Trent£1,501
Install a new boiler near Tamworth£1,521
Install a new boiler near Shrewsbury£1,541
Install a new boiler near Woking£1,665
Install a new boiler near St Albans£1,667
Install a new boiler near Harrogate£1,507
Install a new boiler near Crewe£1,525
Install a new boiler near South Shields£1,545
Install a new boiler near Craigavon£1,387
Install a new boiler near Stafford£1,545
Install a new boiler near Rotherham£1,531
Install a new boiler near Barnsley£1,521
Install a new boiler near Lowestoft£1,617
Install a new boiler near Walsall£1,513
Install a new boiler near Gosport£1,583
Install a new boiler near Dartford£1,623
Install a new boiler near Bognor Regis£1,601
Install a new boiler near Corby£1,595
Install a new boiler near Paignton£1,515
Install a new boiler near Maidenhead£1,671
Install a new boiler near Rochester£1,549
Install a new boiler near Ellesmere Port£1,507
Install a new boiler near Loughborough£1,495
Install a new boiler near Dudley£1,517
Install a new boiler near Bangor£1,527
Install a new boiler near Dewsbury£1,507
Install a new boiler near Mansfield£1,511
Install a new boiler near Margate£1,557
Install a new boiler near Kettering£1,587
Install a new boiler near Cannock£1,517
Install a new boiler near Sale£1,569
Install a new boiler near Taunton£1,515
Install a new boiler near Runcorn£1,603
Install a new boiler near Farnborough£1,643
Install a new boiler near Tynemouth£1,549
Install a new boiler near Hereford£1,507
Install a new boiler near Halesowen£1,525
Install a new boiler near Widnes£1,549
Install a new boiler near Huyton with Roby£1,533
Install a new boiler near Scarborough£1,529
Install a new boiler near Gravesend£1,581
Install a new boiler near Bebington£1,527
Install a new boiler near Kidderminster£1,501
Install a new boiler near Stourbridge£1,525
Install a new boiler near Barry£1,507
Install a new boiler near Smethwick£1,515
Install a new boiler near Dunfermline£1,609
Install a new boiler near Livingston£1,629
Install a new boiler near Weymouth£1,603
Install a new boiler near Brentwood£1,607
Install a new boiler near Barrow-in-Furness£1,821
Install a new boiler near Hamilton£1,517
Install a new boiler near Canterbury£1,539
Install a new boiler near Wellingborough£1,615
Install a new boiler near Sittingbourne£1,609
Install a new boiler near Macclesfield£1,481
Install a new boiler near Bootle£1,541
Install a new boiler near Carlton£1,519
Install a new boiler near Esher£1,645
Install a new boiler near Clacton-on-Sea£1,619
Install a new boiler near Lancaster£1,535
Install a new boiler near Beeston£1,507
Install a new boiler near Banbury£1,617
Install a new boiler near Torquay£1,517
Install a new boiler near Folkestone£1,509
Install a new boiler near Kingswinford£1,515
Install a new boiler near Bloxwich£1,529
Install a new boiler near Bridgend£1,485
Install a new boiler near Welwyn Garden City£1,673
Install a new boiler near Lisburn£1,467
Install a new boiler near Leamington Spa£1,531
Install a new boiler near Washington£1,579
Install a new boiler near Tunbridge Wells£1,623
Install a new boiler near Kirkcaldy£1,597
Install a new boiler near Hinckley£1,497
Install a new boiler near Durham£1,569
Install a new boiler near Cumbernauld£1,631
Install a new boiler near Wokingham£1,653
Install a new boiler near Horsham£1,633
Install a new boiler near Crosby£1,535
Install a new boiler near Yeovil£1,549
Install a new boiler near Thundersley£1,573
Install a new boiler near Altrincham£1,557
Install a new boiler near Willenhall£1,525
Install a new boiler near Christchurch£1,567