Facts and figures last checked on 9 November 2026
Checking the F-gas register before you hire an air conditioning firm
Anyone who fits or services air conditioning in your Ilford home needs two separate things: a company F-gas certificate for the firm, and a personal qualification for the engineer doing the work. Both take minutes to check, and the time to check is before paying a deposit. This guide explains what each covers and the refrigerant rules behind them.
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What does "the F-gas register" actually mean?
Usually the records kept by the bodies that certify companies. Any business, sole traders included, that installs, repairs, maintains or decommissions refrigeration, air conditioning or heat pump equipment belonging to other people needs certifying by one of the approved bodies. For this work GOV.UK names three: Bureau Veritas UK Ltd, Refcom Certification Ltd and F-Gas Register (Quidos). "F-Gas Register" is therefore also the name of one of the three schemes, which is why the search term can confuse. The certificate must be renewed every three years. Source: GOV.UK on company certification.
What qualification must the engineer hold?
A personal F-gas qualification in their own name, needed even when they work for someone else; the firm's certificate is no substitute. GOV.UK sets out four categories:
| Category | What the holder may do |
|---|---|
| 1 | Every activity, on systems of any size |
| 2 | Install, maintain, service and recover refrigerant where a system has less than 3 kg of F gas (less than 6 kg if hermetically sealed) |
| 3 | Recover refrigerant only, within those same limits |
| 4 | Checking for leaks without breaking into the refrigerant circuit |
A typical new 2.5 kW split holds about 0.8 kg, so category 1 or 2 covers fitting it; category 4 alone does not. Sources: GOV.UK on qualifications; Mitsubishi Electric.
How do I check a firm and its engineer?
- Ask the firm for its F-gas company certificate number and which of the three bodies issued it.
- Confirm the number and the company name with that body, and check the certificate is in date; it lasts three years.
- Compare the trading name on the certificate with the one on your quote and invoice; they should match. If another company's certificate is offered, ask who is actually doing the work.
- Ask the engineer who will connect the refrigerant for their personal certificate and category, and note them down.
- Do all of this before any deposit changes hands.
Ask us the same questions and check our answers the same way. Sources: GOV.UK on company certification; GOV.UK on qualifications.
Does a home system need a legal leak check?
Not if it is a single modern room unit on R32 of ordinary size. Compulsory checks begin once a system's charge is equivalent to 5 tonnes of CO2, no less often than every 12 months, rising to twice a year at 50 tonnes. GOV.UK's example at the 5-tonne line is 2.4 kg of R410A, the older refrigerant, which on our sum is about 2 tonnes of CO2 equivalent per kilogram. Mitsubishi's current 2.5 kW split holds 0.80 kg of R32, which its data sheet puts at 0.540 tonnes, around a tenth of the threshold; on our sum it would take about 7.4 kg of R32 to reach it. So a split of that kind needs no legal leak check, while larger systems and older R410A ones may. A yearly service is still sensible, and a firm selling a "mandatory" leak check on a small R32 split should be asked which rule requires it. Sources: GOV.UK on leak checks; Mitsubishi Electric.
Which refrigerants are banned in new equipment?
Two bans matter for homes. Since 2025, new single split systems holding less than 3 kg of refrigerant may not use F gases with a GWP (global warming potential) above 750. New movable units, the kind you wheel between rooms, may not use HFCs whose GWP is above 150. R32's potential is 675 on Mitsubishi's sheet, below the 750 line, which is why splits like it can still be sold. On 27 August 2026 GOV.UK added three exemptions, for single splits used only to cool products, air-to-water single splits and single splits on maritime craft; none applies to a home air-to-air unit. The bans cover new products placed on the market, not systems already installed. Sources: GOV.UK on the bans; Mitsubishi Electric.
What other paperwork should come with a new installation?
Three items besides the F-gas details. An electrical certificate, because Part P treats a home's new circuit as notifiable work; a scheme-registered electrician self-certifies it, and the certificate should reach you within 8 weeks of completion. The MCS 020a noise calculation, on which the permitted development right depends (the noise guide explains it). And a commissioning record of the refrigerant work. Keep them with the warranty; the servicing and repair work that relies on them is listed on our Ilford air conditioning homepage. Sources: IET; GOV.UK on competent persons; Grant UK.
Common questions
My heating engineer is Gas Safe registered. Does that cover air conditioning?
No. Gas Safe registration is for work on gas appliances such as boilers. Refrigerants come under the F-gas rules, which need the company certificate and personal category described above.
Does a sole trader need a company certificate?
Yes. GOV.UK says the company certification rule applies to sole traders as well as larger firms.
How often must a company certificate be renewed?
Every three years. A certificate dated more than three years ago is a reason to ask for the current one.
Sources for this page
- GOV.UK: the certificate a firm installing F gas systems must hold
- GOV.UK: which qualifications a technician needs before working on F gas equipment
- GOV.UK: leak-check intervals for equipment holding F gas
- GOV.UK: the F gas bans on new equipment, with dates
- Mitsubishi Electric: data sheet for the MSZ-LN25VG2 and MUZ-LN25VG2 split, with power input, sound levels and refrigerant (June 2024, in French)
- IET: Part P and electrical work in English and Welsh homes
- GOV.UK: competent person schemes and self-certified building work
- Grant UK: heat pumps and planning in England, including the 37 dB(A) limit (May 2025)
Five things to have handy
Answers to these let us judge, before anyone visits, how involved the job will be.
- Your postcode
- The building: terrace, semi, detached, a flat in a block or over a shop, or business premises
- Whether you own it outright, hold a lease or rent it
- Which room it is, its rough size, and whether it gets the morning or the afternoon sun
- Anything that limits outside changes: a conservation area, a listing, a lease clause or a managing agent
Want to talk about your own home or premises? Our page on air conditioning in Ilford sets out what we fit, how we look after it and where we work.
Services related to this guide
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Air conditioning servicing
Filters, coils and drain cleaned and the system measured against its rating, on any make, with the legal leak check added only where the charge requires it.
Air conditioning repairs
No cooling, water on the floor, frosted pipes or a flashing code: the cause found first, then a price.
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Your name, phone number and postcode are all we need to call you. A word about the room helps us come prepared. You can also call 020 8176 6154.