Hot Water Cylinder Replacement Cost

Three guides, three different answers

BestBuilders, in a guide updated on 22 August 2026, gives a typical UK market range of £750 to £1,400 fitted for a vented copper cylinder and £900 to £3,000 fitted for an unvented one. The cylinder alone is £180 to £450 for vented and £450 to £2,000 for unvented on the same page.

BookaBuilderUK, in a 2026 guide with no publication date, gives a typical UK market range of £1,800 to £3,500 for a standard unvented replacement. It builds that from £700 to £1,800 in materials, £600 to £1,500 in labour, £150 to £400 for disposal and £300 to £800 for optional upgrades. High-specification unvented jobs run from £3,500 to £5,000 and above.

Squote, a pricing knowledge base last verified on 17 May 2026, prices the cylinder only, supplied. Its typical UK market range is £550 to £900 for a 150 litre unvented stainless steel cylinder, £700 to £1,200 for 210 litres and £950 to £1,650 for 250 to 300 litres. A vented copper cylinder of 120 to 210 litres is £180 to £420.

Why do the figures differ so much?

They are not pricing the same job. A vented swap on a gravity system reuses the loft tank, the vent and most of the pipework. An unvented swap adds a cold inlet group, an expansion vessel, a relief valve and a tundish, and it is notifiable work under Part G of the Building Regulations. A guide that folds those parts into its unvented figure will read higher than one that prices the cylinder and a day of labour.

Region is the second gap. BestBuilders says London and the South East typically add 15 to 25 percent. Squote gives a typical UK market range for a plumber day rate of £240 to £360 outside London and £300 to £440 in London.

The third gap is who wrote the page. BestBuilders, BookaBuilderUK and Squote are commercial sites, not independent price surveys. That does not make the figures wrong, but it is a reason to read them as ranges and not quotes.

How much does changing the type of cylinder add?

Changing the arrangement is the largest swing. BestBuilders gives a typical UK market range of £1,300 to £3,000 for a vented to unvented conversion, because the job adds a discharge route, mains-pressure pipework and often electrical changes. A swap that keeps the type, size and position stays towards the lower end.

Specification matters inside a type. Squote lists a heat-pump compatible 210 litre cylinder at a typical UK market range of £950 to £1,800 supplied, well above a standard 210 litre unit at £700 to £1,200. If you are weighing the unvented route, unvented cylinder installation cost covers the extra items line by line.

What do quotes leave out?

Access and making good. BookaBuilderUK gives a typical UK market range of £150 to £600 for making good ceilings or flooring, and notes that tight hatches and corroded pipework add labour. Disposal of a large old cylinder is its own line in some guides.

Findings on the day. Corroded pipework, a seized stopcock or a worn valve group may need replacing while the cylinder is out. A good quote lists these as provisional items and says how they are charged. A quote that does not is hiding a risk in the total.

Building Control. Squote lists an inspection at a typical UK market range of £180 to £350 where the installer cannot self-certify an unvented job, so it is fair to ask any installer who notifies the work and what record you will be given.

How do I read a quote line by line?

A quote you can compare names the cylinder (make, model, litres, vented or unvented, direct or indirect), the valve and safety kit if unvented, the electrics, draining and disposal, making good, and what is provisional. Two quotes with different totals are only comparable once those lines match.

The longer checklist is in cylinder replacement quote checklist. It is worth reading before you ask anyone to price the job.

One habit saves money more reliably than any range: ask every quote to separate the cylinder from labour, valve kit, electrics, disposal and making good. A single lump sum hides which parts are cheap and which are padded. If a quote is itemised, a missing line is easy to spot, such as an unvented job with no tundish or discharge pipe, and an extra line is easy to challenge.

What London Cylinder Specialist charges

A cylinder replacement from London Cylinder Specialist is a fixed £1,450 for labour and miscellaneous parts. The cylinder is priced separately: it is chosen from a price list by type, size and your preference, and LCS recommends the right one for the home. No VAT is charged.

The fitted ranges above fold the cylinder and other items in, so they are market figures for different jobs and are kept apart from this fixed labour price.

If the fault is not yet certain, cylinder troubleshooting and diagnosis is a fixed £180. There is no call-out fee.

How solid is this evidence?

Thinner than it looks. Every figure above comes from three commercial pages, one of them undated, and the ranges overlap only loosely. Other cost pages could not be retrieved when this page was prepared, and no manufacturer price list was available, so there is no independent check on the numbers. Treat the spread as the finding.

The surest way to a real price is to have the cylinder diagnosed first, because a leak from a union or an immersion boss is a far smaller job than a failed shell. Repair or replace a hot water cylinder gives the decision rule, and like-for-like cylinder replacement shows what a straight swap involves.