Rules desk · chart page
F-gas certified installers, electricians and who does what
An F-gas certified installer is a legal requirement for split air conditioning in Great Britain; a Category 2 engineer may work on systems holding under 3 kg of refrigerant.
By the Cooler Indoors desk · figures checked · 4 charts · sources · methods
An F-gas certified installer is the only person who may connect, charge, service or remove a split air conditioner or air-to-air heat pump in Great Britain. The law covers both the engineer and the business that employs them. Wiring has a separate set of rules, and grant schemes add a third layer through MCS.
Source: GOV.UK, Qualifications required to work on equipment containing F gas · checked 29 October 2026
How we read this Category 2 limits on refrigerant charge. Category 1 covers all sizes. Whether a given home unit falls under 3 kg depends on its charge, which the maker's data plate states.
Show the numbers
| Label | kg | Note |
|---|---|---|
| Split or other non-sealed system | 3 | |
| Hermetically sealed system | 6 |
What is an F-gas certified installer?
It is an engineer who holds the right F-gas qualification for the job. Government F-gas guidance is blunt: handling these gases without the correct qualifications is against the law. Category 1 lets an engineer work on any system; Category 2 covers installing, servicing and recovering refrigerant from systems containing less than 3 kg.
Whether a particular home split falls below that line depends on its refrigerant charge, which is printed on the outdoor unit, so ask rather than assume.
Does the company need certification as well as the engineer?
Yes. Any business that installs, repairs, maintains or decommissions F-gas equipment, sole traders included, needs company certification from a recognised body such as Refcom or the F-Gas Register. It is renewed every three years. A qualified engineer working through an uncertified firm does not meet the rule.
Can you buy a split system and fit it yourself?
No. GOV.UK's guidance for sellers says a shop supplying a non-sealed split system must first find out which qualified engineer is going to fit it for the buyer. Buying refrigerant without the qualifications is itself unlawful.
So-called pre-charged kits do not change this. Connecting the refrigerant pipes, pressure testing and opening the valves are F-gas tasks, and the refrigerants page explains why the gases involved are tightly controlled.
Source: GOV.UK, Bans on F gas in new products and equipment · checked 29 October 2026
How we read this Global warming potential relative to CO2. Gas values come from the retained F-gas regulation (R410A calculated as a 50/50 blend). Limits apply to new equipment placed on the GB market; Northern Ireland follows the EU regime instead.
Show the numbers
| Label | GWP | Note |
|---|---|---|
| R410A | 2,088 | Above the 750 limit |
| Single-split limit, under 3 kg | 750 | |
| R32 | 675 | |
| Portable (movable) unit limit | 150 | |
| R290 (propane) | 3 |
Who does the electrical work for air conditioning?
A registered electrician, in most cases. In England, Approved Document P makes a new circuit, a replacement consumer unit and some work in special locations notifiable. That work must be done by someone in a competent person scheme or signed off by building control. If the install needs a new circuit from the consumer unit, it is notifiable.
Wales has its own version, and its list of notifiable work is wider, with outdoor work included. Across the UK the wiring itself should follow BS 7671; the IET confirms that BS 7671:2018+A4:2026 is the current edition.
On video: Purpose of F-Gas regulations
“Purpose of F-Gas regulations”, a video from the Expert Academy - Ideal Heating channel on YouTube. Ideal Heating's training academy explains briefly that F-gas rules exist to keep refrigerant out of the atmosphere, require leak checks and recovery, and require that every engineer handling F-gases is trained and certified. It is their video, not ours, and it loads from YouTube only when you press play.
Source: GOV.UK, Apply for the Boiler Upgrade Scheme: what you can get · checked 29 October 2026
How we read this Boiler Upgrade Scheme grants in England and Wales. Each needs an MCS-certified installer. Scotland's scheme does not fund air-to-air units, and Northern Ireland has no open grant.
Show the numbers
| Label | £ | Note |
|---|---|---|
| Air-to-air | £2,500 | In law since 28 April 2026 |
| Air-to-water | £7,500 | |
| Ground source | £7,500 |
Where do MCS and TrustMark fit in?
They are quality schemes rather than legal licences to handle refrigerant. MCS certifies heat pump products and installers, and the Boiler Upgrade Scheme defines an installer as an MCS-certified person. TrustMark is the government-endorsed scheme for work in and around the home.
There is a catch for air-to-air. MCS said on 8 September 2026 that installers could not yet gain MCS certification for these units, so the £2,500 grant exists in law but has few or no installers able to claim it. We follow its progress on a separate grant tracker as MCS rolls certification out.
Source: DESNZ, Boiler Upgrade Scheme statistics, September 2026 · checked 29 October 2026
How we read this Cumulative counts for air-to-air heat pumps in England and Wales from Table 1.1. A zero here reflects the MCS certification gap, not a judgement on the applications.
Show the numbers
| Label | applications | Note |
|---|---|---|
| Applications received | 157 | |
| Vouchers issued | 0 | None yet |
What if the work involves a gas boiler?
Then a Gas Safe registered engineer must do the gas side. HSE says anyone employed to work on gas appliances in a home must be on the register. An air conditioning engineer is not automatically qualified to disconnect or alter a boiler.
If you smell gas or a carbon monoxide alarm sounds, get everyone out first. Do not use light switches, phones or anything electrical inside. From outside the building, phone 0800 111 999 for the National Gas Emergency Service, or 999 if anyone feels unwell.
| Job | Who | Rule |
|---|---|---|
| Connect, charge, service or recover refrigerant | F-gas qualified engineer at a certified company | GB F-gas regulations |
| New circuit or consumer unit | Registered electrician, or building control sign-off | Part P (England); Welsh Part P |
| Wiring standard | Electrician | BS 7671:2018+A4:2026 |
| Gas boiler disconnection or changes | Gas Safe registered engineer | HSE domestic gas rules |
| Grant-funded heat pump | MCS-certified installer | Boiler Upgrade Scheme |
How can you check an installer before signing?
Ask for the engineer's F-gas qualification category, the company's certification body and number, and the electrician's competent person scheme. For grant work, check the MCS certificate. Make sure the quote names who handles each part, including the electrics.
Questions this data raises
Can an electrician without F-gas papers fit a split air conditioner?
They can run the supply circuit, but they cannot connect or charge the refrigerant pipework. That part needs an F-gas qualified engineer working for a certified company.
How often must an F-gas company renew its certificate?
Every three years, through a certification body such as Refcom or the F-Gas Register.
Is MCS certification a legal requirement to install air conditioning?
No. F-gas qualifications are the legal requirement for refrigerant work. MCS is needed only if you want a Boiler Upgrade Scheme grant.
Does Northern Ireland follow the same F-gas rules?
Northern Ireland sits within the EU F-gas system rather than Great Britain's, so product limits may differ. Ask the installer which F-gas certificates they hold for work there.
Which wiring edition should my electrician be working to?
BS 7671:2018 with Amendment 4 (2026), which the IET lists as the current edition. Amendment 2 became obsolete on 15 October 2026.
Sources for this page
- GOV.UK, Qualifications required to work on equipment containing F gas gov.uk
- F-gas guidance gov.uk
- GOV.UK, Bans on F gas in new products and equipment gov.uk
- Approved Document P assets.publishing.service.gov.uk
- its list of notifiable work gov.wales
- IET electrical.theiet.org
- GOV.UK, Apply for the Boiler Upgrade Scheme: what you can get gov.uk
- MCS mcscertified.com
- TrustMark trustmark.org.uk
- DESNZ, Boiler Upgrade Scheme statistics, September 2026 gov.uk
- HSE hse.gov.uk
All checked 29 October 2026. How we choose and read sources: Methods & sources.