UK cost guide · September 2026

How much does it cost to replace an unvented cylinder in 2026?

Replacing an unvented hot water cylinder like for like, with a mid-range cylinder of the same size in the same place, costs about £1,400 to £2,200 including VAT in an average UK area outside London. A cylinder from a value range costs £1,100 to £1,700, and a top range one £2,100 to £2,800. The published guide we cite gives one wide installed range for any unvented cylinder job, so ours is built up for a like-for-like swap from a cylinder’s price and the labour for replacing one: treat it as a guide.

By Estiquote · Prices reviewed 25 September 2026, next review December 2026 · How we calculate · Updated 10 November 2026

Work out your unvented cylinder replacement cost

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Already have an installer’s price? Check where your quote sits against this range. Still deciding what to do first? Read where to start a home renovation.

Unvented cylinder replacement prices in 2026

Ranges are for a typical home outside London, including VAT, before fees and contingency. Use the calculator for your region and finish.

Unvented cylinder replacement costs by type and finish, UK average outside London, including VAT (September 2026)
Type	Basic	Mid-range	Premium
Unvented cylinder, like-for-like	£1,100 to £1,700	£1,400 to £2,200	£2,100 to £2,800

Unvented cylinder replacement costs by region

Labour costs vary across the UK far more than materials. Unvented cylinder replacement prices in London run about 18% above the UK average outside London, and in Northern Ireland about 9% below it.

Unvented cylinder replacement costs by region: Unvented cylinder, like-for-like, including VAT
Region	Mid-range cost
UK average (outside London)	£1,400 to £2,200
London	£1,700 to £2,600
South East	£1,500 to £2,400
East of England	£1,500 to £2,300
South West	£1,500 to £2,300
West Midlands	£1,400 to £2,200
East Midlands	£1,400 to £2,200
Scotland	£1,400 to £2,200
North West	£1,400 to £2,100
Yorkshire and the Humber	£1,400 to £2,100
Wales	£1,400 to £2,100
North East	£1,400 to £2,100
Northern Ireland	£1,300 to £2,000

Which region is my town in? Brighton, Oxford and Southampton are in the South East; Cambridge and Norwich in the East of England; Bristol, Bath and Exeter in the South West; Birmingham and Coventry in the West Midlands; Nottingham and Leicester in the East Midlands; Glasgow and Edinburgh in Scotland; Manchester and Liverpool in the North West; Leeds, Sheffield and Hull in Yorkshire and the Humber; Cardiff and Swansea in Wales; Newcastle and Sunderland in the North East; and Belfast in Northern Ireland. Somewhere else? Type your postcode into the calculator above and it says which region’s prices it uses.

Want it for your area? See local prices and council building control fees for 92 council areas in England and Wales (not every council yet).

What the price covers

An unvented cylinder is a hot water cylinder fed straight from the cold water mains, with no tank in the loft, so taps and showers get mains pressure. Our price is for replacing one like for like: a new cylinder of the same size in the same place, connected to the pipework, discharge pipe and controls you have now. The discharge pipe is the pipe that carries water safely away if one of the cylinder’s safety valves opens.

Unvented cylinder replacement, like for like, including VAT (September 2026)
Finish	What it might be	UK average outside London	London
Basic	A cylinder from a value range	£1,100 to £1,700	£1,300 to £2,000
Mid-range	A cylinder from a well known brand	£1,400 to £2,200	£1,700 to £2,600
Premium	A top range cylinder, often with a longer warranty	£2,100 to £2,800	£2,500 to £3,300

Built up from a 210 litre cylinder's retail price (about £540 to £1,550 before VAT), fitting labour (£300 to £500) and an Estiquote allowance of £100 to £300 for fittings and taking the old cylinder away. The published guide we cite gives one wide installed range for any unvented cylinder job, not a like-for-like swap, so treat ours as a guide. Not included: converting a vented system (a cylinder fed by a cold water tank in the loft) to unvented; moving the cylinder to a new place; a new route for the discharge pipe; a new boiler, or new boiler controls; building control's fee, if your installer isn't registered with a competent person scheme for unvented hot water systems.

Changing from a tank in the loft? Turning a vented system (a cylinder fed by a cold water tank in the loft) into an unvented one is a bigger job, with new pipework and a new discharge route, so it isn’t priced here. Ask for a quote. If sludge (a build-up of rust and dirt) is clogging your radiators and pipes, the heating may need a power flush too: a deep clean in which a machine pumps cleaning chemicals through them. That costs about £480 to £720 including VAT: see new boiler costs.

Who can fit it, and building regulations

Because an unvented cylinder stores hot water under mains pressure, the building regulations require a hot water system to resist the effects of temperature and pressure, to stop the stored water ever going above 100°C, and to carry any discharge from its safety valves safely to where it can be seen (requirement G3(2) and (3)).

In England and Wales, choose an installer with the skills for unvented systems: Approved Document G says the skills can be shown by registration with a competent person scheme for this type of work, or by a current registered operative skills card, a card that certifies the fitter’s own skills with unvented hot water systems (paragraph 3.40). Installing an unvented system is notifiable building work, so building control must be told before work starts (paragraph 3.41), unless the installer is registered with a competent person scheme for unvented hot water systems. Then the installer self-certifies the work and you get a certificate, usually from the scheme (paragraph 3.42; the paragraphs are the same in Approved Document G for England and Approved Document G for Wales; the schemes are listed in Schedule 3 of the Building Regulations). Our price assumes a registered installer; if yours isn’t registered, building control’s fee isn’t included. Ask for the certificate, and keep it with the cylinder’s paperwork.

A Gas Safe engineer isn’t enough on its own. In England and Wales, Gas Safe registration is for gas work (GOV.UK), and it doesn’t cover unvented hot water cylinders: ask for their unvented qualification, or their competent person scheme registration for unvented systems (Approved Document G, paragraph 3.40; the same paragraph for Wales).

In Scotland and Northern Ireland the building rules are set separately, so ask your installer, or your council’s building control (building standards in Scotland), what applies before work starts.

What's included in these prices

Included

Taking out the old unvented cylinder and taking it away
A new unvented cylinder of the same size, in the same place, with its safety valves and expansion vessel (a small tank that takes up the extra water as it heats and expands)
Connecting it to the existing pipework, discharge pipe and controls
Commissioning (setting it up and checking it works safely) by an installer registered with a competent person scheme for unvented hot water systems, who tells building control for you

Not included

Converting a vented system (a cylinder fed by a cold water tank in the loft) to unvented
Moving the cylinder to a new place
A new route for the discharge pipe
A new boiler or new boiler controls
A power flush for the heating (a deep clean of the radiators and pipes), about £480 to £720 with a boiler job
Building control’s fee, if your installer isn’t registered with a competent person scheme
Your contingency

What drives the cost

Cylinder size and make. A bigger cylinder, or a top range one with a longer warranty, costs more.
The pipework you have. Old valves or pipes, or a discharge pipe that needs changing, add work.
Access. A cylinder in a tight cupboard or in the loft takes longer to swap.
Where you live. London prices run about 18% above the UK average outside London.

Planning, regulations and VAT

See who can fit it, and building regulations above.

Checklist: what to ask installers to confirm

Print this or save it as a PDF, one copy for each quote. Mark each line included, separate or not confirmed as quotes come in. An empty amount means unknown, not free.

Print one copy for each quote you are comparing
Item	What to confirm	Included? Amount?
Cylinder	Make, model and size in litres, and the warranty. Check the maker's warranty terms: many need a yearly service.
Valves and vessel	New safety valves and expansion vessel included.
Discharge pipe	Whether the existing discharge pipe is kept, and whether it meets the rules.
Installer	Registered with a competent person scheme for unvented hot water systems, so they can self-certify the work: ask for their registration. If they only hold a skills card, building control must be told before work starts, and its fee is extra.
Certificate	Building regulations notification or self-certification, and who arranges it.
Disposal	Taking the old cylinder away.

Questions people ask

Does a new boiler include a new cylinder?

Not in our boiler prices. A system or regular boiler swap keeps the cylinder you have, and changing to a combi takes it out. See new boiler costs.

Does replacing an unvented cylinder need building regulations approval?

In England and Wales, installing an unvented system is notifiable building work. An installer registered with a competent person scheme for unvented hot water systems self-certifies it and you get a certificate; otherwise building control must be told before work starts (paragraphs 3.41 and 3.42 of Approved Document G for England and for Wales). In Scotland and Northern Ireland, ask your installer or building control what applies.

Sources and method

Our ranges combine published 2026 UK cost guides, industry data and our own survey of council fees. We check them every quarter. They are budget ranges, not quotes: always get at least three detailed written quotes. Read how Estiquote estimates work, or download the full cost data.