HOW TO HIRE · PLUMBING & HEATING

How to hire an immersion heater fitter in the UK
The checks, the questions and the paperwork.

No register applies to an element swap, but wiring has rules and unvented cylinders need a qualified installer. The checks and the price.

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THE 60-SECOND VERSION

Hiring an immersion heater fitter in five steps

  1. Vented or unvented?A cylinder with no loft tank feeding it is usually unvented — a different job.
  2. Element or more?Just the element, or a thermostat, timer or new switch too.
  3. Who does the wiring?Any new circuit or spur by a registered electrician.
  4. Ask about the cylinderIf it is leaking or heavily scaled, replacing it may make more sense.
  5. Draining included?Draining and refilling should be in the price.

BEFORE YOU BOOK

Check before you book

No register applies

No licence or register applies to immersion heater fitters in England, Wales, Scotland or Northern Ireland, so anyone may offer an immersion heater swap. For an immersion heater swap, two legal lines remain: gas work belongs to a Gas Safe registered engineer, and new fittings must meet your nation's water fittings rules.

Ask whether any part of the immersion heater swap touches gas, and if it does, who on the team is on the Gas Safe Register.

Unvented hot water cylinder (England)

Approved Document G makes fitting an unvented hot water system notifiable building work in England. An installer on a competent person scheme for it self-certifies; otherwise building control must be told before the immersion heater work starts.

Ask for the scheme membership or unvented hot water card, and for the compliance certificate after the immersion heater work. gov.uk →

Electrical work and the Building Regulations

If the immersion heater needs a new electrical supply, that is electrical work under the Building Regulations in England and Wales. Work in a bathroom or shower room is notifiable, and so in Wales is work in a kitchen or outdoors: it needs an electrician on a competent person scheme, or building control.

Search the electrician on the Registered Competent Person Electrical register and ask for the certificate for the immersion heater wiring. electricalcompetentperson.co.uk →

Public liability insurance, including water damage

No law requires a plumber to be insured for the immersion heater swap, but one leaking joint can ruin a ceiling. The Consumer Rights Act 2015 gives you the right to the immersion heater swap done with reasonable care and skill — insurance is what makes a claim against the fitter worth something.

Ask the fitter for the insurer's name and whether the policy covers water damage.

VAT

Fitting an immersion heater is standard-rated at 20%; the reduced 5% applies only to listed heating appliances fitted under a qualifying grant for someone aged 60 or over, or on certain benefits. Registration is compulsory above £90,000 of taxable turnover, and a registered firm has to charge it and itemise it rather than fold it into the price.

Ask the immersion heater fitter whether the price includes VAT, and for the VAT number. gov.uk →

“Is my cylinder vented or unvented, and does that change the immersion heater job?”

A good answer: A look at the cylinder, and if it is unvented, a fitter qualified for unvented systems.

“Is the element, thermostat and draining all in the immersion heater price?”

A good answer: Yes, each listed.

“Does the wiring need changing?”

A good answer: A plain answer; new wiring goes to a registered electrician.

“What if the element boss is seized?”

A good answer: A stated plan, and what happens if the cylinder is damaged.

“Is the cylinder worth keeping?”

A good answer: An honest view if it is leaking or very old.

“Can you fit a timer?”

A good answer: Yes, priced, so the immersion heater runs only when needed.

Getting the quote right

  • Element and thermostat named
  • Draining and refilling included
  • Any timer, switch or wiring, and who does it
  • Who actually attends — the fitter, and who does any wiring, employed or subcontracted
  • The VAT number, and VAT at 20% shown separately

Walk away if

  • Works on an unvented cylinder with no unvented qualification
  • Rewires the supply with no certificate
  • Does not check for leaks after refilling
  • Forces a seized boss without warning you of the risk
LOW
£120
TYPICAL
£180
HIGH
£250

What an immersion heater fitter costs: £120–£250 per install

Immersion heater swaps are a fixed price per install; a timer, new wiring or a new cylinder are extra. Immersion Heater Installation price guide →

Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.

KNOW WHAT TO LOOK FOR? NOW FIND ONE

Immersion heater fitters near you, with the badges that matter shown

ID checked, trader status and one score from every review — on the card, before you message anyone. Nearest first. No account needed to look.

Or post the job free and let them come to you.

  1. IsolatePower and water off, cylinder drained enough.
  2. RemoveOld element unscrewed with the right spanner.
  3. FitNew element and thermostat with a fresh seal.
  4. RefillCylinder refilled and checked for leaks.
  5. TestPower on, the heater tested.

Immersion heater
An electric element that heats water in a cylinder.
Unvented cylinder
A mains-pressure hot water cylinder with safety valves.
Vented cylinder
Fed by a cold tank in the loft.
Element boss
The threaded fitting the element screws into.
Thermostat
Switches the element off at the set temperature.
Fused spur
A switched, fused connection for a fixed appliance.

AFTER

When the job is done

Check the hot waterHot at the taps in the expected time.
Look for leaksRound the element boss after refilling.
Keep the invoiceWith any electrical certificate.
Write the reviewSay what the immersion heater fitter did well on the immersion heater and what they did not. If it fell short, use the make-it-right step first, so the immersion heater fitter can put it right before you publish.

STEP 1Complain to the immersion heater fitter firstMessage the immersion heater fitter with the date, what went wrong and the fix you want. If the immersion heater fell below reasonable care and skill — the test in the Consumer Rights Act 2015 — sections 55 and 56 give you a free redo or a cut in the price.
STEP 2Use the make-it-right stepRate the immersion heater below four stars and you are asked whether the immersion heater fitter should see the complaint first; we keep it moving until it is answered, then you review.
STEP 3Trading Standards, through the helplinesAn immersion heater fitter who will not engage can be reported through the consumer helplines, which pass cases to Trading Standards — Citizens Advice (0808 223 1133) in England and Wales, Advice Direct Scotland (0808 800 9060), Consumerline (0300 123 6262) in Northern Ireland.
STEP 4Small claims, if money is owedAn unpaid refund or repair bill from the immersion heater goes to small claims: £10,000 is the limit in England and Wales, £5,000 in Scotland using simple procedure, and £5,000 in Northern Ireland — all designed to be used without a solicitor.

Hiring an immersion heater fitter: questions people ask

No register applies to an element swap. New wiring must meet the Building Regulations, and an unvented cylinder in England needs a qualified installer.

A mains-pressure cylinder with safety valves; fitting one is notifiable in England under Approved Document G.

For any new wiring, an electrical certificate; for an element swap, an invoice.

£120–£250 per install, about £180 typical. Read the immersion heater installation price guide for the factors behind it; to see fitters near you, enter your town above.

If it is leaking or badly scaled, ask for both prices.

One to two hours for most replacements.

MORE GUIDES

More hiring guides in plumbing & heating

How to hire: Water Tank InstallationHow to hire: PlumberHow to hire: Boiler Service & RepairHow to hire: Solar Thermal InstallationHow to hire: Central Heating InstallationHow to hire: Pipework InstallationHow to hire: Leak RepairHow to hire: Emergency PlumberAll 701 hiring guides →

Immersion heater fitters near you

Immersion heater fitters in LondonImmersion heater fitters in ManchesterImmersion heater fitters in BirminghamImmersion heater fitters in GlasgowImmersion heater fitters in BelfastAll immersion heater fitters on Locufy →

Sources — checked October 2026

  1. Water Supply (Water Fittings) Regulations 1999, regulation 5 — notice to the water undertaker
  2. Water Supply (Water Fittings) Regulations 1999, regulation 6 — contractor's certificate
  3. Water Supply (Water Fittings) (Scotland) Byelaws Extension Order 2024
  4. Water Supply (Water Fittings) Regulations (Northern Ireland) 2009
  5. Gas Safety (Installation and Use) Regulations 1998, regulation 3
  6. gov.uk — Approved Document G: sanitation, hot water safety and water efficiency (England)
  7. Registered Competent Person Electrical register
  8. gov.uk — Approved Document P: electrical safety in dwellings (England)
  9. Consumer Rights Act 2015, section 49 — reasonable care and skill
  10. Citizens Advice — more help with a consumer issue (England)
  11. Energy-saving materials and heating equipment (VAT Notice 708/6) — 2.23 Other energy-efficient products (standard-rated); 3 Grant-funded heating (5%)
  12. GOV.UK — VAT rates
  13. GOV.UK — Register for VAT: when to register