Guide for homeowners · Cost benchmark
Boiler service cost in Northern Ireland: 2026 prices for oil and gas
By The NI Trades Research Desk, Editorial & Research · 8 minute read
Published 19 August 2026 · Last reviewed 19 August 2026
Reviewed every quarter and updated whenever prices, platforms or recommendations change in the Northern Ireland market.
A gas boiler service in Northern Ireland costs £80 to £120 in 2026. An oil boiler service costs £90 to £160. You will also see advertised offers well under both, and those are not scams: they are a different, smaller visit. Knowing which parts separate the two is the difference between comparing quotes properly and just picking the cheapest number.
It matters more here than almost anywhere. Oil is the dominant home heating fuel in Northern Ireland, which means most households are buying the more complicated service, from a smaller pool of registered engineers, in the same six-week window every autumn.
What a boiler service costs in NI, 2026
| Service | Typical NI range |
|---|
Gas boiler service Gas Safe registered engineer, full service with a written record. | £80 to £120 |
Oil boiler service OFTEC registered engineer. Higher than gas because a nozzle and oil filter are replaced as part of the job. | £90 to £160 |
Gas safety certificate (CP12) on its own Landlord requirement. Cheaper bundled with a service than bought separately. | £60 to £95 |
CP12 plus annual gas service, same visit The usual landlord package, and better value than booking the two separately. | £110 to £170 |
Landlord oil safety certificate, added to a service The oil equivalent for rented property, issued at the same visit. | about £20 on top |
Sources: our own NI benchmark set, published in the NI Home Improvement Cost Index 2026 and the gas safety certificate guide, cross-checked in August 2026 against advertised service prices from Northern Ireland heating firms and against per-engineer listings for Belfast on the HaMuch trade-rate directory. These are benchmarks for judging a quote, not an estimate for your boiler. Note also that many NI sole traders are not VAT registered, so a quote from a one-person firm may genuinely carry no VAT while a larger company’s does.
About those £55 and £60 offers
Several larger NI heating companies advertise a service from around £55 to £70, and some include a gas safety certificate in that price. Those offers are real. What they generally exclude is parts: read the small print and you will usually find electrodes, combustion seals, and on oil the nozzle and filter, charged separately if they are needed.
So the honest way to read the market is not cheap versus expensive. It is a smaller visit versus a fuller one. An entry-priced service where nothing needs replaced can be excellent value. The same visit on a five-year-old oil boiler that needs a nozzle ends up in the same range as everyone else once the parts go on.
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Why oil costs more than gas, and what that buys
A gas service is inspection, cleaning and testing. Nothing is routinely replaced. An oil service is partly a parts job, because oil burns dirtier: soot builds in the heat exchanger, the nozzle that atomises the fuel wears and is replaced every year, and the oil filter is changed. That difference is why the oil range sits above the gas one.
Which leads to the single most useful question you can ask when comparing oil quotes: is a new nozzle included? Two oil quotes £50 apart are often both honest prices for genuinely different visits. One is a clean and a combustion check; the other replaces the consumables that actually fail on the first cold morning.
A full oil service should include
- ✓A new nozzle fitted, not just cleaned. This is the part that most separates a £70 service from a £120 one.
- ✓Oil filter changed and the fuel line checked for weeping joints.
- ✓Heat exchanger brushed out and soot removed.
- ✓Photocell cleaned and tested, and the burner lockout tested.
- ✓Combustion and efficiency reading taken with a flue gas analyser.
- ✓A written service report you keep, in OFTEC format.
A full gas service should include
- ✓Burner, heat exchanger and main components inspected, cleaned and tested.
- ✓Flue checked, and seals and pipework examined.
- ✓Gas pressure and combustion checked.
- ✓Safety devices tested.
- ✓A written record, and a gas safety certificate if that is part of the price you agreed.
A cheaper service missing two of these is not cheaper, it is smaller. Ask what is included before you compare, and get the answer in writing.
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Book it in August, not November
Heating systems sit idle through a Northern Ireland summer. Sediment settles in the oil tank, the nozzle sits unburned, seals dry slightly. Then the first properly cold week arrives, thousands of systems are asked to work hard on the same morning, and the ones carrying a marginal fault fail together.
That is also the week every OFTEC and Gas Safe engineer in the country becomes unreachable. The cost of leaving it is not really the service price, it is the difference between a planned visit at a time that suits you and an emergency callout with a cold house and no leverage on price.
August: the easy booking. Engineers have availability and you pick the date.
September: still fine, but book in the first half of the month.
October: the practical deadline, and the month to have the oil tank topped up by.
November onward: you are in the queue with everyone whose boiler has already failed.
The rest of the year is laid out in our month-by-month NI home calendar.
Who is allowed to service your boiler
Two separate registers, two separate competences. Oil boilers should be serviced by an OFTEC-registered technician. Gas appliances must be worked on by a Gas Safe registered engineer. Plenty of NI engineers hold both, and plenty hold only one.
Check the registration on the official register rather than accepting a card at the door. Registrations lapse through non-renewal, and the card in someone’s wallet does not prove the registration is current today. Our guide on verifying tradesperson credentials in NI walks through checking each one, and it takes about two minutes.
If your boiler is near the end of its life rather than due a service, our oil boiler replacement cost guide covers when repair stops making sense, and the NI grants guide covers what heating funding is actually open in 2026.
If you have been let down before
You are not the problem.
More than one in five UK homeowners has had a trade simply not turn up, and about one in seven has been cancelled on at the last minute. It is the most common story in home improvement, and it is exactly what this platform was built to end.
✓Every trade is vetted before they can respond: photo ID, insurance, two references phoned, registers checked.
✓A maximum of three respond. You compare, you choose, and nobody sees your details until you decide.
✓Let down after hiring? Report it. Trades who let homeowners down are removed from the platform.
The vetting is already done. All that is missing is your job.
Common questions
Frequently asked questions
How much is a boiler service in Northern Ireland?
In 2026, a gas boiler service in NI typically runs £80 to £120, and an oil boiler service £90 to £160. Oil costs more because a proper oil service replaces consumable parts, a nozzle and an oil filter, and includes brushing soot out of the heat exchanger, none of which a gas service involves. You will also see advertised offers from around £55 to £70, and those are genuine, but they usually exclude parts such as electrodes, seals and the oil nozzle, so they describe a smaller visit rather than a cheaper version of the same one.
How much does an oil boiler service cost in NI?
Expect £90 to £160 in 2026 from an OFTEC-registered engineer for a full service including a new nozzle, an oil filter change, a soot brush-out and a written report. Cheaper advertised prices generally cover a clean and a combustion check with the nozzle and filter charged separately if needed. Before comparing prices, ask each engineer one question: is a new nozzle included? That single answer usually explains the entire difference between two quotes.
Why is an oil boiler service more expensive than a gas one?
Because an oil service is partly a parts job. Oil burns dirtier than gas, so the heat exchanger accumulates soot and needs brushed out, the nozzle that atomises the fuel wears and is replaced annually, and the oil filter is changed. A gas service is inspection, cleaning and testing with no routine consumables. The gap between the two ranges is largely those parts and the time to fit them, which is also why a suspiciously cheap oil service is worth asking questions about rather than simply booking.
When should I book my boiler service in Northern Ireland?
August to early October, before the heating season starts. Systems sit idle all summer, and the first genuinely cold week is when sludged tanks, worn nozzles and marginal pumps all fail at once, which is also the week every OFTEC and Gas Safe engineer in the country gets booked out. Booking in late summer means you choose the date; booking after the first cold snap means waiting, and a breakdown then is an emergency callout rather than a planned service.
Is a boiler service a legal requirement in Northern Ireland?
For an owner-occupier, no. There is no law requiring you to service your own boiler, though most manufacturers require an annual service to keep the warranty valid, so skipping it can quietly cost you far more than the service. For landlords it is different: gas appliances in rented property must be checked annually by a Gas Safe registered engineer and a certificate issued. Whatever the legal position, an annual service on any fuel-burning appliance is a safety check, not just a maintenance one.
Who is legally allowed to service my boiler in NI?
It depends on the fuel. Oil-fired boilers should be serviced by an OFTEC-registered technician, and gas appliances must be worked on by a Gas Safe registered engineer. They are separate registers covering separate competences, and plenty of NI engineers hold both. You can and should verify the registration on the official register rather than accepting a card at the door, since registrations lapse. Servicing your own gas boiler is not a legal option.
Does a boiler service include a gas safety certificate?
Sometimes, and it is worth asking rather than assuming. Several NI firms include a gas safety certificate in an advertised service price, which is why a bundled service can look cheaper than buying a certificate alone. Others quote the service and charge the certificate separately. On the oil side, a landlord oil safety certificate is normally around £20 on top of the service. Get it stated in writing before the visit, because it is the most common source of a bill that does not match the quote.
Should I fill my oil tank before winter?
It is the common advice from NI heating engineers, for two reasons that have nothing to do with speculating on price. A fuller tank has less air space inside it, which means less internal condensation, and that condensation is where the water and sludge that wreck nozzles and pumps comes from. Second, demand on oil suppliers climbs sharply once the cold arrives and again around the holidays, so lead times stretch when you can least afford them. Nobody can promise a cheaper month, since oil tracks the wider market, but ordering ahead of the rush means you are not buying in an emergency.
What to do next
Four steps before you sign anything.
1
Decide which service you actually need: oil or gas, and whether a landlord certificate has to come with it.
2
Ask every engineer the same question before comparing prices, is a new nozzle and filter included, so you are comparing the same visit rather than the same word.
3
Post the job free and compare up to three vetted NI heating engineers, with OFTEC or Gas Safe checked at application, while there is still availability.
About the author
The NI Trades Research DeskEditorial & Research · Northern Ireland
NI Trades content is researched and written in house in Northern Ireland: figures are compiled from written NI quotes and official published sources, drafted with the help of AI tools as disclosed in our editorial standards, then checked against the cited primary sources before publishing. Every page carries its sources and review date, and corrections are made fast when readers or tradespeople spot an error.
Researched in house, checked against the cited primary sources and reviewed on the date shown on each page.
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