Boiler Service vs Gas Safety Certificate (CP12): What's the Actual Difference?

We get asked this more than you'd think, usually by a landlord who's been told they need "the gas thing" and isn't sure if that's the same as the service they already pay for every year. It isn't, and mixing the two up can leave a landlord thinking they're covered when they're not. Here's the straight version.

What a boiler service actually covers

A service is about your boiler specifically: its performance, its safety, and how long it keeps running without a breakdown. Our engineers strip down and clean the heat exchanger, check the burner and gas pressure, test the safety devices, inspect the flue, and clear the condensate trap, among other checks. You get a written record at the end. It's good practice for any boiler owner and it's usually what manufacturers mean when they ask for proof of annual boiler service York cover to keep a warranty valid. Full detail on exactly what's checked is in our boiler service checklist, linked above.

What a CP12 actually covers

A CP12, properly called a Landlord Gas Safety Record, is a legal document. It's the certificate a Gas Safe registered engineer issues after checking every gas appliance in a rented property, not just the boiler: the gas hob, a gas fire, any gas water heater, as well as the flues and ventilation for each one. It confirms the property is safe to let, and it's a requirement under the Gas Safety (Installation and Use) Regulations 1998, not an optional extra. Our full breakdown of what's checked and what's required is on our CP12 landlord certificate page.

The core difference in one line

A service is about keeping your own boiler running well for years. A gas safety certificate York landlords rely on is a legal safety sign-off covering every gas appliance in the property, renewed every 12 months, with a copy owed to the tenant. One is good practice for anyone. The other is a legal obligation specifically for landlords, and it doesn't quietly happen as a side effect of the other.

Who needs a service: any boiler owner, to protect the warranty and catch small faults early.
Who needs a CP12: landlords letting a property with gas appliances, every 12 months, full stop.
Does a service count as a CP12? No. A service only looks at the boiler. A CP12 covers every gas appliance in the property and comes with its own certificate.
Does a CP12 include a full service? Not automatically. It confirms the appliances are safe to use; it doesn't include the full strip-down clean that keeps a boiler's warranty and long-term performance in good shape.

Do I need both?

If you're a homeowner living in your own property, you just need the annual service. If you're a landlord, you need the CP12 every year without exception, and the service on top of that is still worth having so the boiler itself stays reliable for your tenants and doesn't land you with an avoidable breakdown call mid-tenancy. Because an engineer is already on site checking the boiler closely for the landlord gas certificate York requires, a lot of our landlord customers book both at once and save themselves a second visit.

Getting both sorted in York

If you're not sure which one you're actually due, or you've got a few rental properties with renewal dates scattered across the calendar, we can check what you need and get it booked in one go. Call 01904 206190 or WhatsApp 07414 291034 and we'll sort out exactly what's outstanding before anyone turns up.

Last updated November 2026 by The Boiler Doctor, York.