HOW TO HIRE · PLUMBING & HEATING

How to hire a boiler installer in the UK
The checks, the questions and the paperwork.

Only a Gas Safe registered engineer may fit a gas boiler, and the installation must be notified. The checks, the quote and the certificate you keep.

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THE 60-SECOND VERSION

Hiring a boiler installer in five steps

  1. Check the Gas Safe RegisterGet the installer's licence number and check it by text to 85080 or on 0800 408 5500 before you accept a quote.
  2. Ask for a survey, not a phone priceA boiler is sized to the home's heat and hot water needs; a proper installer looks before quoting.
  3. Compare like with likeSame boiler type and output, flue route, filter, system clean and controls on every quote.
  4. Agree who notifies building controlThe engineer registers the installation, and a compliance certificate follows. Say it in the quote.
  5. Keep the paperwork togetherCommissioning record, compliance certificate and the maker's warranty registration in one folder.

BEFORE YOU BOOK

Check before you book

Gas Safe Register

Under regulation 3 of the 1998 Gas Safety (Installation and Use) Regulations, and Northern Ireland's 2004 Regulations, installing a gas appliance for pay is lawful only for members of the HSE-approved class — the Gas Safe Register. There is no exception for a straight swap.

Text 'Gas' and the licence number to 85080, or call 0800 408 5500, and match the name. gassaferegister.co.uk →

Boilers on the back of the card

Registration is by category. The back of the Gas Safe ID card lists the appliances the engineer is qualified for; for this job it has to show gas boilers or central heating.

Read the back of the card on the survey visit, before any deposit. hse.gov.uk →

Building Regulations compliance certificate

A new or replacement boiler is notifiable building work in England. A Gas Safe engineer self-certifies it, and gov.uk says a compliance certificate should reach you within 8 weeks.

If nothing has arrived after 8 weeks, contact Gas Safe Register with the installation address. gov.uk →

VAT on the quote

HMRC's Notice 708/6 is clear that gas boilers are standard-rated at 20% even when efficient; only qualifying heating controls fitted in a home are zero-rated until 31 March 2027.

Check the boiler line carries 20% and that any zero-rated controls are listed on their own. gov.uk →

VAT

A new boiler and its fitting are standard-rated at 20%; the reduced 5% applies only to the grant-funded share of the work for a qualifying person — aged 60 or over, or receiving certain benefits — in the home they live in. 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.

If a grant pays part of the boiler, ask the installer to show which share is at 5% and which at 20%, and for the VAT number. gov.uk →

“Are you Gas Safe registered for boilers, and what is your licence number?”

A good answer: A number you can check now, and a card whose back lists boilers. A firm that sends someone else should name them.

“How did you size the boiler for this house?”

A good answer: From the number of bathrooms, the hot water demand and the heat the rooms need — not from the old boiler's sticker.

“Is the price like for like, or does it include moving the boiler?”

A good answer: A clear scope. A new position means new gas, water and condensate pipes and a new flue, and costs more.

“Does the boiler installation include a system clean and a filter?”

A good answer: Yes, or a clear reason why not. A dirty system shortens a new boiler's life, and some warranties ask for both.

“Who registers the boiler installation, and when will I get the certificate?”

A good answer: They notify it themselves, and the compliance certificate follows; gov.uk says within 8 weeks.

“What warranty does the boiler carry, and what keeps it valid?”

A good answer: The maker's warranty length, whether it needs registering, and the yearly service it depends on.

“What happens to the old boiler and any tanks?”

A good answer: Disconnected safely and taken away, stated in the quote with any extra cost.

Getting the quote right

  • The boiler make, model and output, and the type — combi, system or regular
  • Flue route, condensate pipe, filter and system clean named as line items
  • Controls included, and whether any qualifying controls are zero-rated
  • Removal of the old boiler and tanks, and making good around the new one
  • Who notifies building control, and the commissioning and warranty registration
  • Who actually attends to fit the boiler — the Gas Safe engineer by name, and whether employed or subcontracted
  • The VAT number, with VAT at 20% on the boiler and labour as a separate line

Walk away if

  • No Gas Safe licence number, or a card without boilers on the back
  • A price over the phone with no survey of the house
  • 'You don't need a certificate for a swap'
  • A large deposit before the boiler is even ordered
  • Pressure to sign the same day with a disappearing discount
  • No mention of the flue or the condensate pipe in the quote
LOW
£1,800
TYPICAL
£2,800
HIGH
£4,500

What a boiler installer costs: £1,800–£4,500 per install

Boiler installations are quoted as a fixed price for the job after a survey; the boiler type, the flue route and any pipework changes set the figure. Boiler 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

Boiler installers 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. Survey and isolateThe engineer checks the old system, then isolates gas, water and power before removing anything.
  2. Clean the systemThe heating system is flushed so old sludge does not reach the new boiler; a filter goes on the return.
  3. Fit boiler and flueThe boiler, flue, condensate pipe and controls are fitted to the maker's instructions.
  4. Test and commissionGas tightness test, flue checks and combustion readings, recorded on the commissioning checklist.
  5. Notify and hand overThe installation is notified, you are shown the controls and pressure, and the paperwork is left with you.

Combi boiler
Heats water on demand with no hot water cylinder.
System boiler
Works with a hot water cylinder but no loft tanks.
Condensate pipe
Carries acidic water from the boiler to a drain; it can freeze if run outside badly.
Magnetic filter
Catches iron sludge in the heating water before it reaches the boiler.
Commissioning checklist
The maker's record of the readings taken when the boiler is first run.
Compliance certificate
Confirms notifiable building work met the Building Regulations; issued after notification.

AFTER

When the job is done

Keep the compliance certificateIt is what a buyer's solicitor asks for. If it has not come within 8 weeks, chase it.
Check the commissioning recordThe engineer fills in the boiler's commissioning checklist with readings; ask for a copy.
Register the warrantyConfirm the maker's warranty is registered in your name and diarise the first service.
Review the visitA few lines on the boiler installation help the next household choose. If there is a problem, the make-it-right step sends it to the boiler installer before your review appears.

STEP 1Complain to the boiler installer firstSay what is wrong with the boiler installation and what you want done about it. Under section 49 of the Consumer Rights Act 2015 the boiler installation had to be carried out with reasonable care and skill; if it was not, you can ask the boiler installer to put it right at their own cost (section 55) or for money off (section 56).
STEP 2Use the make-it-right stepGive the boiler installation fewer than four stars and you can send the issue to the boiler installer first; we stay on it until there is an answer, and then your review is posted.
STEP 3Unsafe or unregistered gas workReport it to Gas Safe Register, which investigates illegal gas work for the Health and Safety Executive. A missing compliance certificate is also raised with Gas Safe Register.
STEP 4Small claims, if money is owedAn unpaid refund or repair bill from the boiler installation 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 a boiler installer: questions people ask

Yes. Fitting a gas boiler is gas work, and in all four UK nations only engineers on the Gas Safe Register may do it for pay.

A Building Regulations compliance certificate after the installer notifies the work — gov.uk says within 8 weeks in England — plus the commissioning record and the maker's warranty papers.

Yes, 20%. Gas boilers are standard-rated even when efficient; only qualifying heating controls fitted in a home are zero-rated until 31 March 2027.

£1,800–£4,500 per install and around £2,800 typical, with a like-for-like combi swap at the low end. The boiler installation price guide explains the range; your town in the search box above shows installers who cover it.

Not from the Boiler Upgrade Scheme, which pays towards heat pumps and some biomass boilers, not gas boilers. Compare a heat pump quote if you are eligible.

Usually a day for a like-for-like swap and two to three days where the boiler moves or the system changes.

MORE GUIDES

More hiring guides in plumbing & heating

How to hire: Boiler ReplacementHow to hire: Boiler Service & RepairHow to hire: Central Heating InstallationHow to hire: Power FlushingHow to hire: Gas EngineerHow to hire: Air Source Heat PumpHow to hire: Radiator InstallationHow to hire: Gas Safety CertificateAll 701 hiring guides →

Boiler installers near you

Boiler installers in LondonBoiler installers in ManchesterBoiler installers in BirminghamBoiler installers in GlasgowBoiler installers in BelfastAll boiler installers on Locufy →

Sources — checked October 2026

  1. Gas Safety (Installation and Use) Regulations 1998, regulation 3
  2. Gas Safety (Installation and Use) Regulations (Northern Ireland) 2004, regulation 3
  3. HSE — Gas Safe Register: the scheme, its coverage and the ID card
  4. Gas Safe Register
  5. gov.uk — building regulations: use a competent person scheme
  6. gov.uk — VAT on energy-saving materials and heating equipment (Notice 708/6)
  7. gov.uk — apply for the Boiler Upgrade Scheme
  8. Consumer Rights Act 2015, section 49 — reasonable care and skill
  9. nidirect — the small claims process (Northern Ireland)
  10. Energy-saving materials and heating equipment (VAT Notice 708/6) — 3.3 Central heating systems (5% only when grant-funded); 2.23 otherwise standard-rated
  11. GOV.UK — VAT rates
  12. GOV.UK — Register for VAT: when to register