What does CP12 actually stand for?
The CP12 is shorthand for 'Certificate of Proof — 12 months' — the original Gas Safe Register form for the Landlord Gas Safety Record introduced in the mid-1990s. The Council for Registered Gas Installers (CORGI) issued the first version; Gas Safe Register took over in 2009 when it replaced CORGI as the statutory body. Most landlords, agents and engineers still call the certificate a 'CP12' even though the official terminology is 'Landlord Gas Safety Record'. The two names refer to the same document.
Why landlords must have one — the law
The legal obligation comes from the Gas Safety (Installation and Use) Regulations 1998. The regulations require any landlord renting a property with one or more gas appliances to commission an annual inspection by a Gas Safe registered engineer. A copy of the certificate must be given to the existing tenant within 28 days, and to any new tenant before they move in. The landlord has to keep their copy for at least two years. The Health and Safety Executive (HSE) enforces the regulations, and breaches are a criminal offence — fines run up to £6,000 per appliance and in serious cases custodial sentences have been imposed.
What an engineer actually checks
On a CP12 inspection the Gas Safe registered engineer goes through every gas appliance and the gas supply itself. The full check list:
- Visual inspection of each gas appliance (boiler, hob, oven, gas fire) including its position, condition and fixing
- Gas tightness test on the supply pipework to confirm no leaks
- Combustion performance analysis (where required) using a flue gas analyser
- Inspection of every flue and chimney, including external terminals, for blockages and integrity
- Ventilation check on every appliance
- Operational check that safety devices (flame failure, oxygen depletion, overheat thermostat) are functioning
- Pipework inspection for any visible safety issues, illegal connections or unsafe routing
- Operational check that the appliance is fundamentally working and not at risk of producing carbon monoxide
How often you need one
Every twelve months. The inspection has to be carried out no more than twelve months after the previous one, and at least every twelve months thereafter. To avoid lapsing, most landlords book the new inspection between months ten and twelve of the previous certificate's validity — booking earlier gives you a buffer if something needs remedial work. Booking later puts you at risk of a gap, which the regulations don't allow.
How much a CP12 costs in Aberdeen in 2026
Aberdeen prices for a CP12 sit in the £74-£106 range for a single-appliance property in 2026, with most engineers quoting in the high £70s to low £90s. Multi-appliance properties (boiler plus gas hob plus gas fire, for example) usually carry a small increment of £10-£20 per additional appliance. Combined inspections — CP12 plus an annual boiler service done in the same visit — typically work out £20-£40 cheaper than booking the two separately. Portfolio landlords usually negotiate bulk pricing once they have five or more properties scheduled annually.
Who can legally issue one
Only a Gas Safe registered engineer with the correct categories on their card can issue a CP12. The engineer's Gas Safe ID number must appear on the certificate. You can verify any engineer's registration at the Gas Safe Register's free check service at gassaferegister.co.uk before they start work. Anyone offering 'cheap CP12s' without a Gas Safe number on the document is committing a serious criminal offence — and the certificate is worthless legally.
Short-lets, Airbnb and the Scottish licensing angle
If the property is rented to paying guests — long-term tenancy, short-term Airbnb, holiday let, Serviced Accommodation — and it has any gas appliance, the same regulations apply. Scotland's Short-Term Lets Licensing Order 2022 made matters more concrete: most Scottish councils, including Aberdeen City and Aberdeenshire, now require evidence of a valid CP12 as part of the short-term-let licence application or renewal. Trying to operate without one risks both prosecution under the 1998 regulations and licence refusal under the 2022 order.
What to do if your certificate has expired
Book an inspection as soon as possible. There is no formal 'grace period' in the legislation — the moment the previous certificate passes its twelve-month anniversary, you are technically in breach. In practice, HSE enforcement focuses on serial offenders rather than landlords who slip a week, but you should not rely on tolerance. Ring a Gas Safe registered engineer, book the soonest available slot, and update your records. If you have multiple properties on different annual cycles, a simple spreadsheet or calendar reminder is enough to avoid this entirely.
Need this done in Aberdeen?
Ring Belmont. Gas Safe registered, no call-out charge, we answer the phone first ring.