Gas Safety Certificate: What It Is, Why It Matters, and Who Needs One

Gas is convenient and popular in UK homes and businesses, but without regular maintenance, it can also be hazardous. Faulty gas appliances can produce carbon monoxide, ignite fires, or result in severe harm. That’s why the Gas Safety Certificate, also referred to as a CP12, exists: to verify that gas appliances are inspected, safe, and legally compliant.

Whether you are a property owner, renter, or property manager, knowing gas safety regulations isn’t simply about checking boxes — it’s about keeping people safe and preventing severe legal and financial repercussions.

What Is a Gas Safety Certificate?

A Gas Safety Certificate is a document that confirm gas appliances, pipework, and flues within a property have been inspected and are safe. It must only be done by a Gas Safe registered engineer after an inspection has taken place.

The certificate contains:

• The details of the engineer and the Gas Safe registration number
• The address of the property
• Date of inspection carried out
• A list of appliances and their location
• Outcomes of every safety check
• What faults were discovered, and what needs to be done about them
• Confirmation that the system is safe (or not)

These were previously referred to as CP12 certificates, a name that originated from the previous CORGI gas registration system. The Gas Safe Register has taken over from CORGI, but the name CP12 is still in common use.

Who Needs One?

1. Landlords

If you let a property — including homes, flats, HMOs or holiday lets — you must have an up-to-date gas safety certificate every 12 months.

You must also:

• Provide a copy to tenants within 28 days of the inspection
• Hand it over to the new tenants prior to occupation
• Maintain records for a minimum of two years

This includes private landlords, housing association landlords, student landlords and Airbnb-style short-term holiday lets. To not comply can result in substantial fines or prosecution under the Gas Safety (Installation and Use) Regulations 1998. 

2. Homeowners

There is no law requiring owners, but getting gas appliances inspected every year is highly recommended. A faulty gas fire or boiler may not be detected until it is too late. An annual inspection provides reassurance and typically safeguards appliance guarantees.

3. Businesses and Commercial Premises

If your business uses gas — whether in a restaurant, shop, office, or warehouse — you’ll likely need a commercial gas safety certificate. These checks are similar but apply to larger or more complex systems.

What Does a Gas Safety Check Involve?

During a safety inspection, a registered engineer will:

• Visually check gas appliances and flues
• Test for leaks
• Check gas pressure and flow rates
• Ensure ventilation is adequate
• Inspect safety devices
• Examine the flame and combustion
• Check that the appliance is safe to operate
• If all checks are fine, the engineer will provide a certificate, usually on the same day.
• If there is an issue, they can:
• Label the appliance as unsafe
• Switch it off
• Report what needs fixing or replacing

You should not operate an unsafe gas appliance until it has been repaired and certified safe by a competent engineer.

What Appliances Are Included?

Gas safety inspections inspect any permanently fitted gas appliance, such as:

• Boilers
• Gas fires
• Cookers and hobs
• Pipework
• Flues and chimneys

Portable appliances (such as camping stoves) aren’t covered unless they’re fixed permanently to the gas supply.

How to Obtain a Gas Safety Certificate

Inspections and valid certificates can only be performed by engineers on the Gas Safe Register.

To locate a competent nearby engineer:

• Go to the official Gas Safe Register website
• Use the postcode checker
• Request to be shown the engineer’s Gas Safe ID card when they arrive
• Checks take between 30 minutes and an hour, depending on the number of appliances being checked.

Costs vary, but most residential checks are around £60-£100. Commercial premises or larger houses will be more expensive.

What Happens If You Don’t Have One?

As a landlord, not having a gas safety certificate is not only dangerous — it’s against the law. Penalties include:

• Fines up to £6,000 per incident
• Voided landlord insurance
• Claims from tenants for injury or loss
• Forced property repairs or rehousing
• Prosecution — including prison in serious cases

For homeowners, there is no legal penalty, but the risks include concealed faults, appliance failure, or health problems due to gas leaks or carbon monoxide poisoning.

Staying Organised

To prevent missed deadlines and remain compliant:

• Set reminders for yearly inspections
• Use the same reliable engineer where possible
• Keep a copy of every certificate (digital or printed)
• Inform tenants in advance when checks are due

Numerous engineers now provide yearly service plans or text/email reminders — convenient for busy agents and landlords dealing with numerous properties.

Last Words

A Gas Safety Certificate isn’t merely a technical requirement — it’s an important aspect of keeping your property secure. As a landlord, homeowner, or entrepreneur, getting regular gas checks prevents accidents, saves lives, and avoids expensive problems down the line.

Always employ a Gas Safe registered engineer, never put off inspections, and respond quickly if there are defects. Compliance is easy — and will help save lives.