Facts last checked 17 September 2026
The short answer
Smart Energie's fixed price for an annual gas boiler service is £89 inc VAT (September 2026), and a service plan that books the same service for you each year is £89, paid yearly. A proper service follows the manufacturer's schedule: a flue gas analyser reading, a gas rate check against the data plate, seals, the condensate trap and the safety devices. Keep it yearly: Worcester Bosch, Vaillant, Glow-worm, Baxi and Ideal all make the annual service a condition of their guarantees. A service plan is not breakdown cover, and it pays for no repairs.
How much does a boiler service cost?
Prices for a gas boiler service vary by area and by what the visit actually includes, and there is no official national price to compare against. The useful comparison is what you get for the money: the length of the checklist, whether the combustion reading is recorded, and whether a report is left with you.
| Visit | Fixed price | What it covers |
|---|---|---|
| Annual boiler service | £89 | Full Gas Safe service to the manufacturer's schedule, with a written checklist and a photo of the analyser reading. |
| Service plan, paid yearly | £89 | The same service, with the reminder and the booking done for you. No breakdown or repair cover. |
| Gas safety certificate and service together | £129 | For landlords: the yearly gas safety record and the service in one visit. |
| Boiler diagnostic visit | £89 | Includes the first 30 minutes. Any repair is quoted at a fixed price before work starts, and the £89 comes off a new boiler bought from us within 30 days. |
Manufacturers are clear that the guarantee does not pay for the service itself. Vaillant's and Glow-worm's terms both state that the cost of annual servicing is not included, and Worcester Bosch's say the guarantee does not include the cost or provision of annual servicing. Budget for it every year from the day the boiler goes in.
What should a proper boiler service include?
A service is not a look at the boiler and a sticker. Each manufacturer publishes a maintenance schedule in the installation and servicing manual, and the engineer should work through it. Vaillant's schedule for its ecoFIT pure combi, for example, lists these yearly tasks, among others:
- A combustion analysis with a flue gas analyser: the carbon monoxide (CO) and carbon dioxide (CO₂) content and the CO/CO₂ ratio, measured and then measured again after the work.
- A gas rate check, confirming the gas flow matches the data plate and sits within the manufacturer's tolerances.
- A visual check of the heat exchanger and burner seals, and of the air and flue pipe and its terminal.
- Cleaning and refilling the condensate trap, and checking the condensate pipe is sound, leak-tight, draining correctly and protected from frost outside.
- A check of the heating water for clouding, inhibitor and pH, and of the hot water flow rate.
- A tightness test on the connections, a test run of heating and hot water, and the results written into the Benchmark service record.
Gas safety law sets a floor under that. After working on a gas appliance, a registered engineer must examine the effectiveness of the flue, the supply of combustion air, the operating pressure or heat input, and the appliance's operation so it functions safely, which is where the safety devices are proved. Baxi's guidance adds that most services take around half an hour and that you should receive a full service report. Only sign it if every part was done.
How often should a boiler be serviced?
Once a year. The Health and Safety Executive strongly advises that all gas appliances, flues and pipework are serviced at least annually by a Gas Safe registered engineer, and notes that around 7 people a year die from gas-related carbon monoxide poisoning. Every manufacturer guarantee in the next section asks for the same interval.
Book it for late summer or early autumn if you can. The boiler has been idle for heating for months, so a fault found then is found before you depend on it.
Can skipping a service void your boiler guarantee?
Yes. Long manufacturer guarantees are conditional, and the annual service is one of the conditions in every set of terms we checked:
| Manufacturer | Servicing condition | Other conditions and what happens if missed |
|---|---|---|
| Worcester Bosch | Serviced annually by Bosch or another competent, officially certified engineer, with details in the service record | Registered within 30 days of installation; extended terms need an accredited installer and a Greenstar system filter |
| Vaillant | Serviced annually by a Gas Safe registered engineer to the manufacturer's instructions, recorded in the Benchmark logbook | Registered within 30 days, or the guarantee reverts to 12 months from installation |
| Glow-worm | Serviced annually by a Gas Safe registered engineer to the manufacturer's instructions, recorded in the Benchmark logbook | Registered within 30 days, or the guarantee reverts to 12 months from installation |
| Baxi | An annual service | Registered within 30 days and a completed Benchmark checklist, or the warranty reverts to one year; the magnetic filter must be fitted and maintained, or it reverts to two years |
| Ideal | Serviced by a Gas Safe registered engineer at the end of each 12 month period, or the warranty lapses | Registered within 30 days, or the guarantee is reduced to 12 months |
The same rule sits behind every guarantee term shown in our boiler prices: Manufacturer guarantees depend on registration, the manufacturer's own system filter (fitted in every price) and a yearly service. Some longer terms also depend on installer accreditation, which we confirm in writing with your price. Keep every service report. If you move house, Baxi notes the warranty stays with the boiler as long as the new owner keeps up the annual service. For what the tiers and terms cost, see how much a new boiler costs.
Is a service plan the same as breakdown cover?
No, and it is worth being certain which one you are buying. The £89 plan above is the annual service with the reminder and the booking handled for you. That is all it is.
| Service plan | Breakdown cover | |
|---|---|---|
| What you pay for | Planned maintenance once a year | Call-outs and repairs when something fails, up to the policy's limits |
| Repairs and parts | Not included | Included within the policy's terms and exclusions |
| Emergency call-outs | Not included | Usually the main benefit |
| Keeps the guarantee conditions met | Yes, if the service is done every year | Only if the policy also includes the annual service |
| What to check before buying | What the service includes, and the price next year | Excess, claim limits, pre-existing faults, waiting periods and exclusions |
What happens if the engineer finds a fault?
If the fault is a safety issue, industry procedure classes it as 'At Risk' or 'Immediately Dangerous', and both carry the same label: 'Danger Do Not Use'. HSE is clear that it is illegal to use a gas appliance you suspect is unsafe. If the boiler works but something is failing, you should get a fixed repair price before any work starts. A separate £89 diagnostic visit includes the first 30 minutes, and the £89 comes off a new boiler bought from us within 30 days.
Whether to fix or replace is a separate question, covered in repair or replace your boiler.
How do you check the engineer is qualified?
Anyone working on gas appliances in a home must be on the Gas Safe Register and competent in that type of work. HSE points out that the engineer's competencies are listed on the back of their Gas Safe Register ID card, so ask to see it. You can also check with Gas Safe Register on 0800 408 5500. Our Gas Safe registration number is 921521.
If you let a property, the yearly gas safety record is a legal duty, and it is not the same thing as a service. See landlord gas safety certificates.
Common questions
How long does a boiler service take?
Baxi's guidance is around half an hour for most boilers. A visit that follows the full manufacturer schedule, with the casing off, the condensate trap cleaned and two analyser readings, can take longer. A five-minute visit is not a service.
Do I need a service if my boiler is working fine?
Yes. A boiler can run while producing more carbon monoxide than it should, and the analyser reading is how an engineer finds that. The yearly service is also what keeps most manufacturer guarantees in force.
Does a new boiler need servicing in its first year?
Yes. Ideal's terms, for example, require a service at the end of each 12 month period, and Vaillant, Glow-worm, Baxi and Worcester Bosch all require an annual service. The first one is due around the first anniversary of installation.
Is a boiler service the same as a landlord gas safety check?
No. A gas safety check is a legal safety inspection with a written record; a service is maintenance to the manufacturer's schedule. Landlords can have both in one visit, which is £129 at our fixed price.
Can I get a boiler service on the same visit as another job?
Often, yes. Tell us what else you need when you get in touch and we will say whether it fits one visit.