Gas Safety Certificate London — CP12 from £65

A Gas Safety Certificate (CP12) in London typically costs £65–£120 depending on the number of appliances. A single-appliance CP12 (just a boiler or just a gas hob) starts from £65. A combined certificate covering a combi boiler and gas hob costs £75–£95. If you add a gas fire, expect to pay £90–£120. Same-day or next-day appointments cost £15–£25 more. Our prices include the engineer visit, the full gas safety inspection, and the CP12 certificate issued on the same day.

A CP12 (also called a Landlord Gas Safety Record or LGSR) is the official document confirming that all gas appliances, pipework and flues at a rental property have been inspected by a Gas Safe registered engineer and found safe to use. Under the Gas Safety (Installation and Use) Regulations 1998, landlords must have all gas appliances and flues at their rental properties checked annually by a Gas Safe engineer. Failure to comply is a criminal offence with fines up to £6,000 or six months in prison. A copy of the current CP12 must be given to existing tenants within 28 days of the check, and to new tenants before they move in.

A Gas Safe inspection covers: checking that all gas appliances (boiler, gas hob, gas fire, gas oven) are operating safely and correctly; inspecting gas supply pipework for leaks using a pressure test; checking flues and chimneys are unobstructed and venting combustion gases safely to outside; verifying ventilation is adequate for each appliance; checking flame failure devices and safety controls; and testing for carbon monoxide production. The engineer also checks gas tightness of the supply and records appliance operating pressures. The full inspection takes 45–90 minutes depending on the number of appliances.

If a gas appliance fails the inspection, the engineer categorises the fault: 'Immediately Dangerous' (ID) — the appliance is disconnected and must not be used until repaired; 'At Risk' (AR) — the appliance can remain in use short-term but the fault must be fixed promptly; 'Not to Current Standard' (NCS) — the appliance doesn't meet current regulations but isn't immediately dangerous. For ID faults, the engineer will disconnect the appliance on the spot and issue a warning notice. A CP12 will still be issued documenting the fault. The landlord must arrange repair before reconnecting the appliance. We carry common spare parts and can often repair and re-certify on the same visit.

A Gas Safety Certificate (CP12) is valid for 12 months from the date of inspection. Landlords must renew it annually. To avoid any lapse in cover, book the renewal 1–2 weeks before the current certificate expires. If you've lost your previous certificate, a new inspection is required — we cannot issue a CP12 without physically inspecting the appliances. We recommend keeping a digital and physical copy of your CP12 and setting a reminder in your calendar 6 weeks before expiry.

Yes. While the CP12 is a legal requirement only for landlords, homeowners can request a gas safety inspection for peace of mind, before selling a property (some buyers' solicitors request it), or after buying a property with an unknown gas appliance history. For homeowners we issue a Gas Appliance Service & Safety Report (not a formal CP12) which covers the same checks. This costs the same as a landlord CP12. We recommend homeowners have gas appliances checked every 2 years at minimum, or annually if any appliances are more than 10 years old.