R32 Refrigerant: A Straight Guide for Commercial Buyers

An office manager I know inherited a nine-storey building in Croydon last year, and with it a spreadsheet listing forty-one air conditioning outdoor units, three refrigerants and no installation dates. When two of the oldest R410A splits failed in the same fortnight, every quote she got back proposed R32 machines, and every one assumed she knew what that meant and whether she should care.

She should, and so should you if you are specifying or inheriting split and VRF air conditioning. This is what R32 is, in the numbers that matter to a buyer rather than a chemist.

R32 is the refrigerant that has replaced R410A in almost all new split and much new VRF air conditioning sold in Britain. It is a single-component HFC with a GWP of 675, roughly a third of R410A's 2,088 on the GOV.UK figures the regulation uses, and it carries an A2L safety class: low toxicity, mildly flammable. New single split systems holding less than 3kg have effectively been R32-or-lower since January 2025, when refrigerants with a GWP of 750 or more were banned from that equipment. Your existing R410A systems are still legal and still serviceable, and the decision about what replaces them is simpler than the trade makes it sound.

What R32 actually is

R32 is difluoromethane, chemical formula CH2F2, a hydrofluorocarbon known on the official list as HFC-32. It has been around for years as one half of R410A, a fifty-fifty blend of R32 and R125. What changed is that manufacturers stopped blending it and started using it neat. R32 is simply the current chapter of the gases air conditioning has run on.

A single component matters for service. Blends can fractionate as they leak, changing composition in the pipework, which is why R410A must be charged as a liquid and recovered wholesale. R32 behaves the same way every time, so recovery and reuse are simpler for whoever holds your service contract.

It is still an F gas. GOV.UK's list covers "hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) or sulphur hexafluoride (SF6)", and HFC-32 sits on it at a GWP of 675 (Fluorinated gases (F gases), GOV.UK). Same page, R410A at 2,088. Those are the AR4 values the GB regulation works from, not the higher AR5 figures quoted in carbon reporting, and mixing the two gets your compliance maths wrong.

R32 GWP and what it buys you under the quota

Why the industry moved is arithmetic. The HFC phase-down is denominated in tonnes of CO₂ equivalent, so every kilogram of refrigerant consumes GWP times its mass in quota. A kilo of R410A burns 2,088 units. A kilo of R32 burns 675. The same cooling capacity costs the supply chain roughly two thirds less quota, which is why R32 equipment is what manufacturers want to sell you.

Do not read 675 as "safe from the phase-down". R32 is inside the quota system and stays inside it. The next step lands on 1 January 2027, a 22.6 per cent cut in what can be placed on the GB market, and we have set out what that quota step does to refrigerant supply separately. R32 survives it far better than R410A, but it is a lower-GWP HFC, not a destination. Treat it as the sensible medium-term choice, not the last refrigerant your building will ever use.

The January 2025 ban that settled the split market

Some of this has already stopped being a choice. The retained F-Gas Regulation's Annex III prohibits "Single split air-conditioning systems containing less than 3 kg of fluorinated greenhouse gases" where those gases have a GWP of 750 or more, with a prohibition date of 1 January 2025 (Regulation (EU) No 517/2014, Annex III, legislation.gov.uk).

R410A at 2,088 is over that line. R32 at 675 is under it by 75 points. So new single splits are R32 by default, because close to nothing else qualifies. The ban catches small single splits only. Multi splits and VRF hold well over 3kg and sit outside this prohibition, and their squeeze comes through the quota instead. Same direction, slower.

Is R32 flammable, and what A2L means in an occupied office

Yes, mildly, and the classification tells you how mildly. Under ISO 817, refrigerants get a toxicity letter and a flammability number. R410A is A1: low toxicity, no flame propagation. R32 is A2L: low toxicity, lower flammability, a band for gases that can ignite but burn so slowly a flame front barely travels. It is a different world from A3 gases like propane, which ignite readily and drive the strict charge limits in our piece on natural refrigerants.

For the people sitting under the cassette unit, A2L changes nothing they will notice. The systems are sealed, and the charges are sized against the room volume at design stage under EN 378. Where A2L genuinely bites is at the two ends of the machine's life. At installation, the fitter must respect the manufacturer's minimum floor area and keep refrigerant joints out of concealed unventilated voids. At service, the engineer needs A2L-rated recovery equipment and must control ignition sources while the circuit is open.

The legal umbrella is DSEAR, the dangerous substances and explosive atmospheres regulations. HSE's duties include that employers "find out what dangerous substances are in their workplace and what the risks are" and "identify and classify areas of the workplace where explosive atmospheres may occur and avoid ignition sources (from unprotected equipment, for example) in those areas" (Dangerous Substances and Explosive Atmospheres, HSE). Your contractor carries most of that. Your part as operator is humbler: know what gas is in the system, keep the F-gas records current, and do not let a general handyman near the pipework.

R32 vs R410A in plain numbers

	R410A	R32
Type	Blend of R32 and R125	Single-component HFC
GWP (GOV.UK, AR4)	2,088	675
Safety class	A1, not flammable	A2L, mildly flammable
Charge for the same duty	Baseline	Lower, because R32 carries more cooling per kilogram
New single splits under 3kg	Banned from January 2025	Permitted, under the 750 line
Quota exposure per kilogram	High and worsening	About a third of R410A's
Can it replace the other in an existing system	No	No. Neither is a drop-in

The efficiency question comes up in every tender. Like-for-like R32 machines tend to test modestly better on seasonal efficiency, partly the gas, partly that a new machine is a newer design. Treat any single percentage a salesman quotes with care, but the direction is real.

The CO₂ equivalent arithmetic drives your legal duties, so it is worth doing once. GOV.UK's method is to "multiply the mass of the gas (in metric tonnes) by the gas's global warming potential (GWP)", with the worked example that 10kg of R404A at 3,922 gives 39.2 tonnes CO₂ equivalent (Calculate the carbon dioxide equivalent quantity of an F gas, GOV.UK). Run the same sum on air conditioning gas: 10kg of R410A is 20.9 tonnes CO₂e, 10kg of R32 is 6.8. One large R410A VRF system can cross a leak-check threshold that an equivalent R32 installation stays well under.

R454B: the other R410A replacement

R32 is not the only answer the manufacturers reached. R454B blends R32 with the HFO R1234yf, and several major brands have chosen it for their next generation of larger equipment, including some VRF ranges and chillers. The US EPA lists it under the trade name Opteon XL41, safety class A2L, at a GWP of 470 (Substitutes in residential and light commercial air conditioning, US EPA).

Same A2L handling, slightly lower GWP than R32, and a blend rather than a single component. From a buyer's chair the distinction barely matters today: you choose the machine, and the refrigerant comes with it. Where it matters is a decade out, on service. Two A2L gases across one estate means your contractor needs the kit and the records discipline for both. Ask that question before the second one arrives, not after.

What R32 means for the R410A system you already own

Nothing retrofits. R32 is not a drop-in for R410A, the pressures and safety design differ, and anyone offering to "convert" your system should be shown the door. Your R410A plant stays R410A until the day it is replaced.

That day is not here yet for most buildings. The R410A phase-down bites on supply and price rather than legality, so the plan is to keep the plant tight, fix leaks properly instead of topping up, and let condition decide the timing. The full judgement is in what the R410A phase-out means for UK systems. The short version: a healthy R410A VRF with years in it is worth keeping, and a leaker needing gas every summer is a replacement conversation at 2026 refrigerant prices. Planned air conditioning maintenance tells you which one you own, because a system with service history is a system you can make a decision about.

The F-gas leak check duties that come with either gas

The duties are set by CO₂ equivalent, not by kilograms, which is where the GWP difference turns into paperwork. GOV.UK sets the frequency: "at least once every 12 months" from 5 to less than 50 tonnes CO₂e, "at least once every 6 months" from 50 to less than 500, and "at least every 3 months" at 500 or more, with fitted leak detection doubling each interval. Hermetically sealed systems are exempt "unless they contain F gas equivalent to 10 tonnes of carbon dioxide" (Checking F gas equipment for leaks, GOV.UK).

Converted into charge, the 5-tonne line sits at about 2.4kg of R410A but 7.4kg of R32. Most single splits therefore carry no routine leak-check duty on either gas, whilst a decent-sized R410A VRF installation can reach the 50-tonne band, at roughly 24kg of charge, where checks run six-monthly. The same system on R32 would need about 74kg to get there. The full compliance picture sits in our guide to the F-Gas rules for businesses, and your contractor should be tracking the bands per system, not per building.

Should your next system be R32

For almost every commercial buyer specifying splits or VRF in 2026, yes, because the question has mostly answered itself. New small splits are R32 by law of the market, and new VRF is R32 or R454B depending on brand. The real decisions sit around the gas:

• Ask what the estate already runs. If everything else is R410A, your next system introduces a second refrigerant and a second service regime. Fine, as long as it is written down.
• Ask who services it and with what. A2L work wants rated recovery machines, vacuum pumps and leak detectors. An F-Gas certificate is the floor, not the ceiling.
• Ask where the indoor units go and what the rooms measure. Charge limits and minimum floor areas are the installer's job to calculate, but they can constrain small comms rooms and meeting booths.
• Ask for the charge and the CO₂e in writing. One line on the quote tells you which leak-check band the system lands in and what your records need to show.

What I would not do is name a refrigerant in a tender. Specify the outcome: GWP under 750, A2L-competent installation, charge declared, EN 378 compliance stated. Let the manufacturers fight over which gas gets them there.

Frequently asked questions

What is R32 refrigerant?

R32 is difluoromethane, a single-component hydrofluorocarbon now used in most new split and VRF air conditioning in the UK. It was previously one half of the R410A blend. Zero ozone depletion potential, a GWP of 675 on the GOV.UK list, and an A2L classification meaning low toxicity and mild flammability.

What is the GWP of R32?

675, on the AR4 basis that the GB F-gas regulation and the GOV.UK list use. Roughly a third of R410A's 2,088. You may see higher figures quoted from the newer AR5 assessment; the legal thresholds in Britain work from the AR4 numbers, so use those for compliance maths.

Is R32 flammable in an office?

It is classified A2L, mildly flammable, but the system is sealed and the charge is sized against the room at design stage. Occupants will never notice the difference from the old R410A kit. Flammability is a live consideration for the installer and service engineer when the circuit is open, not for the people working underneath it.

Can I top up or convert my R410A system with R32?

No. R32 is not a drop-in for R410A, and no reputable engineer will put it in a system designed for anything else. Your R410A system stays on R410A, serviced and leak-tight, until the plant is replaced.

Is R32 being phased out?

Not banned, but not exempt either. R32 sits inside the HFC phase-down, so supply tightens with each quota step, including the 22.6 per cent cut on 1 January 2027. Its GWP of 675 keeps it viable far longer than R410A and sits just under the 750 line in the 2025 single split ban. Expect R32 to stay the mainstream commercial air conditioning gas well into the 2030s.

Should I choose R32 or R454B for a new VRF system?

Choose the machine, not the molecule. Both are A2L and far below R410A on GWP, 675 against 470 on the EPA listing. The manufacturer has already made the refrigerant decision for each range. What matters is that your service contractor is equipped for A2L work and that every gas on your estate is recorded with its charge and CO₂ equivalent.

Getting the specification right before the tender goes out

The buildings that come out of this transition well are the ones with a register: every system, its gas, its charge, its CO₂e and its condition. The ones that struggle are running the guesswork my Croydon office manager inherited, where every breakdown becomes an emergency purchase.

If you are specifying air conditioning for a commercial building, or weighing up an ageing R410A estate, it is worth a conversation before the quotes go out. We design and deliver commercial air conditioning installation across London, and we will tell you plainly where R32 fits, where it does not, and what your existing plant has left in it.

About the author: Ali Elm runs Be Cool Refrigeration & Air Conditioning, a family-run London firm that has been installing, servicing and repairing commercial refrigeration and air conditioning since 2004. His F-Gas certified team has delivered more than 2,000 projects across London and the South East.

Last updated: 30 September 2026