Boiler Service Cost Calculator
An annual service is usually a warranty condition, not an optional extra. This prices the service, the landlord certificate and the two together.
Open the calculator →Price a boiler service in 30 seconds
4 steps. Covers boiler type, whether you need a CP12 certificate, extra gas appliances and region.
How this calculator works
A service and a CP12 are different things and it is worth being clear which you are buying. A service cleans, tests and maintains the appliance. A CP12 is a landlord gas safety record — it certifies that appliances are safe on the day, and it neither cleans nor maintains anything. Landlords need the CP12 every 12 months by law; the service is what actually keeps the boiler working and the warranty intact.
Booking both in one visit is the cheapest route by some margin, which is why the calculator prices the combination rather than adding two separate call-outs. A CP12 must cover every gas appliance in the property, so the extra-appliance question is not optional for landlords.
Boiler service and CP12 costs (2026)
| Service | Typical 2026 cost | Notes |
|---|---|---|
| One-off annual service (combi) | £70–£120 | The standard job |
| One-off service (system / regular) | £80–£130 | Cylinder and extra controls to check |
| Landlord gas safety check (CP12) | £60–£90 | Certificate only, no maintenance |
| CP12 — each additional appliance | +£10–£30 | Hob, fire or heater |
| Combined service + CP12 | £100–£150 | Cheapest route for landlords |
| Manufacturer / warranty-brand service | £99–£180 | Where the warranty demands it |
| Boiler cover plan | £10–£25 / month | Service usually included |
Figures match our boiler service cost guide. Check your warranty terms before booking — some brands require their own engineer, and a missed annual service is the most common reason a warranty claim is refused.
Boiler service calculator FAQs
For warranty purposes, almost always yes — most manufacturers require a documented annual service, and a missed one is the most common reason a claim is refused. It also catches the cheap faults early: a £200 pump replaced on a service visit is better than a failure in January.
A service cleans, tests and maintains the boiler. A CP12 is a landlord gas safety record confirming appliances are safe on the day of inspection — it is a legal duty for rented property every 12 months, and it does not maintain anything. Landlords generally want both, done in one visit.
It depends on the boiler. On a unit under about eight years old with a live warranty, usually not — you are insuring against a risk the warranty already carries. On an older out-of-warranty boiler, £10–£25 a month can be reasonable, but read what is excluded, particularly pre-existing faults and any parts cap.
No, and this is a common and expensive misunderstanding. A CP12 confirms safety on the day. If your warranty requires an annual service, a CP12 alone will not satisfy it — you need the service documented as well.
Related cost guides
- Boiler service cost guide — services, CP12s and cover plans
- Boiler repair calculator — price a specific fault
- Boiler replacement calculator — when a service is not enough
- Building regs for boilers — notification and certificates
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