The Difference Between a Gas Safety Certificate & Boiler Service

This is one of the most common points of confusion we come across at Boilers2Go. People often ask whether a Gas Safety Certificate and a boiler service are basically the same thing.

They’re not — and the difference matters.

While both involve checking gas appliances, they serve very different purposes, and only one of them is a legal requirement. If you’re a landlord, getting this wrong can cause real problems. Even as a homeowner, misunderstanding the difference can lead to missed maintenance and avoidable breakdowns.

What Is a Gas Safety Certificate (CP12)?

A Gas Safety Certificate, often referred to as a CP12, is a legal safety check required for rental properties under the Gas Safety (Installation and Use) Regulations.

Its purpose is simple: to confirm that gas appliances are safe to use on the day of inspection.

A Gas Safe registered engineer will carry out checks that include:

• Making sure gas appliances are operating safely

• Checking flues and ventilation are correctly installed and unobstructed

• Testing pipework for gas tightness

• Confirming safety devices are working as intended

If everything passes, the certificate is issued and is valid for 12 months. If faults are found, they’re recorded — and serious issues must be resolved before a certificate can be provided.

The key thing to understand is this:
a Gas Safety Certificate is about legal compliance and immediate safety, not long-term performance or efficiency.

What Is a Boiler Service?

A boiler service is all about maintenance, not legal paperwork.

It’s a more in-depth inspection of the boiler itself, designed to keep it running efficiently, reliably, and safely over time. While it’s not a legal requirement for homeowners, most manufacturers strongly recommend an annual service — and many warranties depend on it.

During a boiler service, an engineer will usually:

• Inspect and clean internal components

• Check seals, electrodes, and burners for wear

• Test gas pressure and combustion performance

• Assess the flue and ventilation

• Check controls, thermostats, and safety cut-outs

• Flag early signs of faults before they become breakdowns

A good way to think of it is this:
a Gas Safety Check tells you the boiler is safe today, while a service helps make sure it still works properly next winter.

Gas Safety Certificate vs Boiler Service: The Key Differences

Do Landlords Need Both?

In practice, yes.

The Gas Safety Certificate is mandatory, but a boiler service plays a big role in keeping that certificate easy to obtain year after year. A poorly maintained boiler is far more likely to fail a safety check — or develop issues between inspections.

Servicing also helps prevent:

• Mid-tenancy breakdowns

• Emergency call-outs

• Disputes with tenants

• Invalidated boiler warranties

Many landlords combine both checks into one visit to save time and hassle.

What About Homeowners?

If you own your home, you don’t need a Gas Safety Certificate — but skipping boiler servicing is still a false economy.

A regular service helps:

• Reduce the risk of winter breakdowns

• Keep energy bills under control

• Maintain manufacturer warranty cover

• Spot small faults before they turn expensive

We regularly see boilers that just scrape through safety checks but are quietly losing efficiency or heading toward failure — issues that servicing would have caught early.

The Boilers2Go Takeaway

A Gas Safety Certificate and a boiler service are not the same thing — and neither replaces the other.

One keeps you legally compliant.
The other keeps your boiler running properly.

Whether you’re a landlord needing a CP12, or a homeowner wanting peace of mind before winter, the right check at the right time makes all the difference.

At Boilers2Go, all our engineers are Gas Safe registered and carry out both services properly — no box-ticking, no shortcuts, and no surprises.