How to check an air conditioning installer's F-gas certificate

Why it matters

Air conditioning and air to air heat pumps use refrigerants that are fluorinated greenhouse gases, often called F gases. They are powerful climate pollutants if released, and they are under pressure inside the system. UK law controls who can handle them. If an installer is not properly certified, you risk a leaking system, a warranty refused by the manufacturer and, in some cases, a system that has to be redone.

There are two separate things to check: the company and the people.

The company certificate

According to gov.uk, your company, including sole traders, must be certified by an approved body to install or service stationary equipment containing F gas that is operated by others, such as your air conditioning. For stationary refrigeration, air conditioning and heat pumps, gov.uk lists these certification bodies:

Certification body	Website
Refcom Certification Ltd	refcom.org.uk
F-Gas Register (Quidos)	fgasregister.com
Bureau Veritas UK Ltd	bureauveritas.co.uk

Gov.uk also says company certification must be renewed every three years, so check the expiry date.

The engineer’s qualification

On top of the company certificate, each engineer who handles refrigerant needs a personal F-gas qualification. Refcom’s guidance says every person working in the sector must hold one, and gives examples such as City & Guilds 2079, BESA F-gas, CITB J11 and LCL F-gas. Engineers carry a card or certificate for this. It is reasonable to ask the engineer who arrives to show it.

Refcom also says that any sub-contractor working on refrigerant must be properly registered too. If the firm you hire sends a sub-contractor, the same checks apply to them.

How to check, step by step

1. Ask for the company certificate number and which body issued it, before you accept a quote.
2. Search the register of that body. Refcom has a find a member search on its site, and the F-Gas Register has its own lookup.
3. Match the details: company name, address and trading name should line up with your quote.
4. Check the expiry date.
5. Ask who will do the work, and whether they are employees or sub-contractors.
6. Ask to see the engineer’s personal qualification on the day.

If an installer avoids giving a number, or the name on the register does not match the business quoting you, treat that as a warning.

Other checks worth making

F-gas is not the only rule that applies to an air conditioning install in London:

• Electrics: a new circuit is notifiable under Part P in England. It must be done by an electrician registered with a competent person scheme, or notified to building control. See the Planning Portal.
• Planning: ask how they have checked whether your unit is permitted development or needs an application. For a heat pump installed as permitted development, ask for the MCS 020 noise calculation.
• Insurance: public liability insurance, which managing agents and freeholders usually ask for.
• MCS: only relevant if you want the Boiler Upgrade Scheme grant for an air to air heat pump. As of October 2026, the Energy Saving Trust says MCS certification for air to air installers is not yet available.

Why this comes up in Islington

Islington is full of converted Georgian and Victorian houses split into flats, with freeholders and managing agents who need to approve any alteration. Agents commonly ask for the installer’s F-gas certificate and insurance as part of a licence for alterations. With 42 conservation areas and many listed terraces, the council will also want accurate drawings and noise details for any planning application. Our Islington area page covers the local rules, and our guide to air conditioning in a listed building explains the extra consent needed.

What to keep after the install

Keep a folder, paper or digital, with:

• the installer’s company F-gas certificate number
• the commissioning record, including refrigerant type and amount
• the electrical installation certificate or building control notice
• any planning or freeholder consent
• the manufacturer’s warranty registration

You will need these if you sell or let the property, make a warranty claim or have a problem later. Our home air conditioning page explains how the install process runs.

Questions to ask before you book

A few direct questions will tell you a lot about any installer:

1. What is your company F-gas certificate number, and which body issued it?
2. Will your own engineers do the work, or a sub-contractor?
3. What personal F-gas qualification does the engineer hold?
4. Who will do the electrical connection, and will it be certified or notified under Part P?
5. How have you checked whether this needs planning permission?
6. Will you give me the commissioning record, including the refrigerant type and amount?

A properly certified installer will answer these without hesitation. If you are in a flat, your managing agent will probably ask the same questions as part of a licence for alterations, so it helps to have the answers in writing.

If something goes wrong

If you think refrigerant work has been done by someone who is not certified, or a system is leaking after installation, stop using it and get it checked by a certified engineer. Keep all paperwork and photos. A certified company can recover the refrigerant safely, find the leak and put the system right.