Every figure checked against its source on 5 November 2026
Checking an installer on the F-gas register
Ask which approved body certifies the company, take the certificate number, and confirm it with that body. Then ask what qualification the engineer who handles the refrigerant holds. It takes a few minutes, and any installer in Croydon worth hiring will expect the question. Put it to us as well.
Ask for a quote
Name, number and postcode. We ring you to go through it.
What must the company hold?
A company certificate from an approved body before it installs, repairs, maintains or decommissions stationary equipment containing F gas for anyone else. GOV.UK is explicit that sole traders count as companies here. The certificate is renewed every three years. A firm that only works on its own equipment does not need one, and car and van air conditioning is exempt. Source: GOV.UK.
Who are the approved bodies?
For stationary refrigeration, air conditioning and heat pump work, GOV.UK lists three: Refcom Certification, F-Gas Register, run by Quidos, and Bureau Veritas. "F-Gas Register" is the trading name of one of them rather than a single national list, which is why searching for it can be confusing. Find out which of the three the firm belongs to and put the number to that body. Source: GOV.UK.
What must the engineer hold?
| Category | What it covers |
|---|---|
| Category 1 | All activities on any system |
| Category 2 | Installing, servicing, maintaining and recovering refrigerant, limited to systems with a charge below 3kg (below 6kg where the system is hermetically sealed) |
| Category 3 | Recovery only, on systems within those same limits |
| Category 4 | Leak checks that do not break into the circuit |
The qualification belongs to the engineer and goes with them from job to job, whoever employs them. The accrediting organisations named by GOV.UK are City and Guilds, BESA and LCL Awards. Source: GOV.UK.
What should you actually write down?
- The company's trading name exactly as it appears on the certificate.
- The certificate number, its expiry date and the body that issued it.
- The name and category of the engineer who will handle the refrigerant.
- If the work is subcontracted, the same three for the subcontractor.
Keep it with the invoice and the electrical certificate. A mismatch between the name on the certificate and the name on your quote is a reason to ask more questions.
Does a sealed or pre-charged unit avoid the rules?
Partly. A factory-sealed monobloc with no refrigerant joints made on site does not need a certified installer to connect it, because nothing is connected. A split system always does, whatever the box says, because the pipes between the two units have to be joined and charged on site. Any later repair that opens the circuit needs a qualified engineer in both cases. Sources: GOV.UK; Quality Heating.
What if you suspect a firm is not certified?
Ask them first; trading names cause honest confusion. If the answer does not add up, contact the certification body. GOV.UK says that companies working without certification should be reported to the Environment Agency. Source: GOV.UK.
Questions people ask
Is F-gas the same as Gas Safe?
No. Gas Safe is for gas appliances such as boilers and hobs. F-gas is for refrigerants, and holding one says nothing about the other.
Does the engineer who services my unit need it too?
Yes. Maintenance and repair are covered as well as installation, and a Category 4 holder can only leak check.
Are you certified?
Ask us when you ring, write down what we say, and check it with the issuing body exactly as you would with anyone else.
Where these facts come from
Useful to have ready
With these we can give you a straight answer on the first call.
- Your postcode
- Flat, house or business premises
- Who owns the outside wall, if you lease or rent
- Which room, roughly how big, and which way the window faces
- Any conservation area or listing you know of
Ready to go ahead? Air conditioning in Croydon covers what we fit, what we look after and where we travel.
Ready to have it fitted?
Air conditioning installation
A survey, a written price, then units, pipework and electrics fitted properly.
Air conditioning servicing
A yearly check on any make, with the legal leak test where it applies.
Air conditioning repairs
Stopped cooling, dripping, iced up or flashing a code: diagnosed first.
More guides
How much does air conditioning cost?
Unit prices, labour, electrics, running costs and the extras flats add.
Planning permission for air conditioning: when you need it
The permitted development conditions, with Croydon's exceptions.
Can you have air conditioning without an outdoor unit?
Monobloc units explained: what they do well, where they fall short.
Air conditioning in a flat: who has to say yes?
Leases, freeholder charges, the one-unit-per-block rule and office conversions.
Is bedroom air conditioning worth the money?
The 26°C rule, what to try first, fixed or portable, and what a night costs.
Cooling a loft conversion: what actually works?
Why lofts overheat, what Part O misses, and where the units go.
Which size of air conditioner is right for the room?
A room size table, the adjustments that matter, and why bigger is not better.
Portable or fixed: which air conditioning should you buy?
A fair comparison, including when the portable wins.
Prefer a call back?
Leave your postcode and a line about the room, and we ring you. Or ring 020 8194 3009.