How to check an air conditioning installer is legitimate

1. F-Gas certification, and the credential shown by mistake

Split air conditioning systems contain fluorinated refrigerant gases. Handling them is regulated: the engineer needs an individual F-Gas handling qualification, and the company needs to be registered with an F-Gas certification scheme. REFCOM is the main one in the UK, operated by the Building Engineering Services Association.

This is law, not a marketing badge. It is the first thing to check and the easiest to verify.

How to verify it in two minutes

1. Ask for the company's F-Gas or REFCOM registration number.
2. Check it against the scheme's public register.
3. Ask whether the engineer attending holds an individual F-Gas handling certificate.

A legitimate installer answers all three without friction. Reluctance is itself the answer.

2. Insurance you can actually see

Ask for the public liability certificate. It should name the company, show the cover level and an expiry date that has not passed. Installing air conditioning involves core-drilling through external walls and working at height, so this matters more than for most trades.

3. A written, itemised, fixed quote

A quote worth trusting states, explicitly:

• The exact units specified, by model number, with their kW output
• The proposed condenser position
• The pipe run length assumed, and what happens if it turns out longer
• Whether electrical work at the consumer unit is included
• Whether making good and clean-up are included
• What the warranty covers, and who registers it
• The planning position — whether permission is needed

A quote that says "supply and fit air conditioning — £2,400" and nothing else is not a quote. It is an opening position, and the extras arrive later.

4. Reviews you can open in a browser

There is a difference between a review and a claim about reviews. A genuine profile has a URL you can click, dated entries, a mix of scores, and responses from the owner. A number printed on a website with no link behind it can say anything.

It is worth checking that the review platform named actually hosts a profile for that company. Occasionally it does not.

5. A real, checkable business

Three quick checks that take about a minute each:

• Companies House. Free to search. It shows incorporation date and filing history. If a site claims twenty years of experience and the company was incorporated last year, there may be a reasonable explanation — a sole trader incorporating later is common — but it is fair to ask.
• The address. A full address including a building number, not a virtual office or a postcode on its own.
• The phone number. One that is answered, by someone who can talk about your specific job.

Questions worth asking on the phone

Before anyone visits, these six take five minutes and tell you most of what you need:

1. What is your F-Gas or REFCOM registration number?
2. Who will actually carry out the work, and are they F-Gas certified?
3. How do you calculate the unit size for a room?
4. Will my property need planning permission, and how will you check?
5. What is included in the price, and what typically is not?
6. Can I see a recent installation in a property like mine?

Question three matters more than it sounds. The right answer references room volume, glazing, orientation and heat gain. An answer of "we usually put a 5kW in a room that size" means the system will be guessed rather than designed, and an oversized unit will short-cycle, run noisily and wear out early.

Where Climatemix stands on all of this

I am REFCOM registered and F-Gas certified, and fully insured. I will give you the registration number on the phone, send the insurance certificate on request, and quote in writing with the model numbers, condenser position, pipe run and planning position all stated. The engineer who surveys the job is the engineer who installs it, because it is a one-person company.

Ask me the six questions above. Then ask whoever else has quoted, and compare the answers.

General guidance, accurate to the best of my knowledge in August 2026. Regulations and scheme requirements change — check current F-Gas requirements on the relevant scheme's own website before relying on anything here.