Air Conditioning Refrigerant Types
The refrigerant in a system decides its environmental impact and how it must be handled. Two numbers matter most: global warming potential (GWP) and the ASHRAE safety class — and both are pushing the industry towards lower-GWP refrigerants like R32 and R290.
Every air conditioning system runs on a refrigerant, and which one it uses is far from a detail. It sets the global warming potential of any leak, the flammability class that governs how much can be used in a given space, and the F-Gas obligations that follow from the charge.
This guide compares the refrigerants you'll meet — R410A, R32, R290, R407C and R134a — by their GWP and ASHRAE flammability class, and explains why manufacturers are moving away from high-GWP blends towards lower-GWP options such as R32 and propane (R290).
Key takeaways
- GWP measures how much heat a refrigerant traps compared with CO₂ — lower is better for a leak's impact.
- The ASHRAE safety class (A1 non-flammable, A2L mildly flammable, A3 flammable) governs how it can be used.
- R410A (GWP ~2088, A1) dominated older splits but is being phased down for its high GWP.
- R32 (GWP ~675, A2L) is the modern split standard — lower GWP, mildly flammable, so it needs care.
- R290/propane (GWP ~3, A3) is very low-GWP but flammable, so it's used in monobloc and small-charge units.
GWP and safety class — the two numbers that matter
Global warming potential (GWP) expresses how much heat a refrigerant traps relative to carbon dioxide, whose GWP is 1. A refrigerant with a GWP of 2,000 does two thousand times the warming of the same mass of CO₂, so a leak of a high-GWP refrigerant is a serious environmental event — and it also drives the CO₂-equivalent charge that sets F-Gas leak-check frequency.
The ASHRAE safety classification covers flammability and toxicity. The classes you'll meet are A1 (non-toxic, non-flammable), A2L (non-toxic, mildly flammable) and A3 (non-toxic, flammable). Lower-GWP refrigerants tend to be more flammable, which is the trade-off the whole industry is navigating.
The common refrigerants compared
The table sets out the refrigerants you'll encounter, with their approximate GWP, safety class and typical use. The pattern is clear: the older non-flammable blends carry high GWP, while the lower-GWP options accept some flammability in return.
| Refrigerant | GWP | Safety class | Typical use |
|---|---|---|---|
| R410A | 2088 | A1 | Older splits |
| R32 | 675 | A2L | Modern splits |
| R290 (propane) | 3 | A3 | Monobloc / small |
| R407C | 1774 | A1 | Legacy |
| R134a | 1430 | A1 | Chillers |
Why the industry is moving to lower GWP
The F-Gas regime phases down the supply of high-GWP refrigerants over time, so the high-GWP blends steadily become scarcer and dearer. That economic and regulatory pressure is why R410A is giving way to R32 in new splits, and why very low-GWP refrigerants like R290 are appearing in more product ranges.
R32 has become the modern split standard because it has roughly a third of R410A's GWP and is a single component that's straightforward to charge — at the cost of an A2L mild-flammability rating that means charge limits and handling care. R290 goes further still on GWP but its A3 flammable class confines it mostly to monobloc and small-charge units where the refrigerant stays outside occupied spaces.
Lower GWP usually means more flammability
The move to R32 and R290 cuts the warming impact of a leak but raises the flammability class. Charge limits, room-size rules and safe handling matter more with A2L and A3 refrigerants, not less.
What it means on the job
Match the work to the refrigerant. A2L and A3 refrigerants bring charge limits relative to room size, restrictions on ignition sources and specific handling and brazing precautions — you can't treat an R32 or R290 job like an old R410A one.
Whatever the refrigerant, the charge drives the CO₂-equivalent figure that sets your leak-check frequency and F-Gas record-keeping. Work that out from the actual charge and refrigerant so the compliance schedule is right from commissioning.
Frequently asked questions
What is GWP in a refrigerant?
Global warming potential (GWP) measures how much heat a refrigerant traps compared with carbon dioxide, which has a GWP of 1. A refrigerant with a GWP of 2,000 causes two thousand times the warming of the same mass of CO₂, so a lower GWP means a smaller environmental impact from any leak.
Is R32 better than R410A?
For environmental impact, yes — R32's GWP is around 675 against R410A's ~2088, roughly a third. The trade-off is that R32 is an A2L mildly flammable refrigerant, so it carries charge limits and handling requirements that A1 R410A does not.
Why is R290 (propane) only used in some units?
R290 has an extremely low GWP of about 3, but it's classified A3 — flammable. That limits how much can safely be used in an occupied space, so it tends to appear in monobloc and small-charge units where the refrigerant stays outside the room.
From guidance to action
Related guides
F-Gas Certification Explained
What F-Gas certification is, the engineer categories, company certification and your legal obligations handling refrigerant.
What Size Air Conditioning Unit Do I Need?
How to size a room air conditioner from floor area, heat gains and glazing — with a rule-of-thumb table and the proper method.
Split System Air Con Installation Guide
How a split-system air conditioner is installed and commissioned — siting, pipe runs, evacuation, charging and handover.
