Many — and some letting agents — confuse a Gas Safety Certificate (CP12) with a boiler service. They are two entirely different things, both of which are important for your rental property. This guide explains clearly what each one involves, what's included, and why need both.
Contents
What is a Gas Safety Certificate (CP12)?
A Gas Safety Certificate — also called a Gas Safety Record or CP12 — is a legal document that confirms all gas appliances, pipework, and flues at a rental property have been inspected by a Gas Safe registered engineer and are safe to use.
What the CP12 inspection covers:
- Gas tightness test on the pipework
- Flue flow and combustion analysis
- Safety controls and emergency shut-offs
- Operating pressure and burner performance
- Visual inspection of flue terminals and ventilation
What the CP12 does NOT cover:
- Cleaning the heat exchanger or burner
- Flushing the condensate trap
- Checking internal boiler components in detail
- Preventative maintenance or parts replacement
What is a Boiler Service?
A boiler service is a thorough inspection and maintenance service carried out to keep the boiler running safely, efficiently, and reliably. Unlike the CP12 — which is a compliance check — the boiler service is about prevention and maintenance.
- Visual inspection of all external components
- Removal and cleaning of the burner
- Inspection and cleaning of the heat exchanger
- Check and clean of the condensate trap and pipe
- Checking and adjusting the gas pressure
- Checking the expansion vessel pressure
- Inspecting all seals and joints
- Checking the flue and combustion analysis
- Testing all controls and thermostats
- Checking radiator system pressure
Key Differences at a Glance
| Feature | Gas Safety Certificate (CP12) | Boiler Service |
|---|---|---|
| Legal requirement? | Yes — annually | No (but recommended) |
| Purpose | Legal compliance check | Preventative maintenance |
| Covers all gas appliances? | Yes | Boiler only |
| Cleaning included? | No | Yes |
| Certificate issued? | Yes (CP12) | Service record only |
| Duration | 30–60 minutes | 60–90 minutes |
| Cost | from £49 | £85 |
Why Need Both
The CP12 tells you the appliances are safe right now. The boiler service ensures they stay safe and efficient throughout the year. Together they give you:
- Legal compliance — the CP12 satisfies your legal obligation as a
- Tenant safety — the service reduces the risk of breakdowns and carbon monoxide leaks
- Boiler longevity — serviced boilers last significantly longer than neglected ones
- Energy efficiency — a clean, well-tuned boiler uses less gas and saves tenants money
- Warranty compliance — most boiler manufacturers require annual servicing to maintain the warranty
Costs and Bundle Deals
| Service | Price (inc. VAT) |
|---|---|
| Gas Safety Certificate (1 appliance) | £49 |
| Boiler Service only | £85 |
| CP12 + Boiler Service (bundle) | £109 |
| CP12 + Boiler Service + EICR | from £198 |
Frequently Asked Questions
What is the difference between a boiler service and a Gas Safety Certificate?
A Gas Safety Certificate (CP12) is a legal compliance check of all gas appliances — it confirms they are safe to use. A boiler service is preventative maintenance — cleaning and inspecting the boiler internals. Both are needed annually.
Do legally need both a boiler service and a CP12?
The CP12 is a legal requirement. The boiler service is not a specific legal requirement but is strongly recommended, required by most boiler warranties, and expected by many insurers.
Can both be done in the same visit?
Yes. We offer a CP12 + Boiler Service bundle for £109 — carried out by a Gas Safe engineer in a single visit. This saves you £25 compared to booking separately.
How long does a combined CP12 and boiler service take?
Typically 60–90 minutes for a standard property with one boiler.
Is the Gas Safety Certificate issued even if the boiler needs servicing?
Yes, as long as the boiler is safe. The CP12 records whether appliances are safe (pass/fail). Servicing is about performance and maintenance — a boiler can be legally safe but still benefit from servicing.