Refrigerants' classification and GWP — from CFC to natural refrigerants

A refrigerant is not just any refrigerant. Some are non-toxic and non-flammable others are highly toxic or extremely flammable and they affect climate very differently if they escape. As a cooling technician you must be able to read a refrigerant's classification and know what it means for how you work with it — it is not something you can guess at on the system.

§From CFC via HCFC to HFC

The oldest synthetic refrigerants, CFC gases, were found to deplete the ozone layer and were phased out globally after the Montreal Protocol. The successor, HCFC, damaged the ozone layer less but was also phased out. HFC refrigerants, which many systems still run on today, do not damage the ozone layer, but many of them are potent greenhouse gases with a high GWP (Global Warming Potential) — a figure for how much a gas contributes to the greenhouse effect compared to CO2. It is precisely GWP that is now driving the next wave of regulation.

§Safety classification: letter and number

Each refrigerant has a safety classification consisting of a letter and a number. The letter tells about toxicity: A means low toxicity, B means higher toxicity. The number tells about flammability: 1 means no flame propagation, 2L means lower flammability, 2 means flammable, and 3 means highly flammable. A common HFC refrigerant such as R410A is classified A1 — low toxicity, non-flammable. R32, used in many modern heat pumps, is A2L — low toxicity, but slightly flammable, which places new demands on ventilation and installation. Propane (R290) is A3 — highly flammable. Ammonia (R717) is B2L — toxic and slightly flammable at the same time.

§GWP — how strong is the greenhouse effect

GWP måler, hvor meget 1 kg af en gas opvarmer klimaet sammenlignet med 1 kg CO2 over en periode, typisk 100 år. CO2 selv (kølemiddelbetegnelse R744) har derfor GWP = 1. Ammoniak (R717) har GWP = 0. Propan (R290) har et meget lavt GWP, langt under 3. Til gengæld ligger mange traditionelle HFC-kølemidler markant højere — R32 ligger omkring 675, mens R410A, som har været udbredt i airconditionanlæg og mindre varmepumper i årtier, ligger i tusindtals-området. Jo højere GWP, jo alvorligere er konsekvensen, hvis kølemidlet lækker ud i atmosfæren, og jo strammere bliver reglerne om det.

§The F-gas regulation is tightening the screws

The EU's F-gas Regulation (EU) 2024/573, which came into force on March 11, 2024, sets an overall cap on how much HFC gas may be sold in the EU, and the cap is cut year by year. The regulation also introduces specific GWP limits for new systems: from 2027, certain system types with refrigerants above 150 GWP are banned, and from 2029 a limit of 150 GWP applies to smaller split heat pumps and air conditioning up to 12 kW, while larger systems have a limit of 750 GWP. This means in practice that the industry is genuinely moving toward natural refrigerants—CO2, ammonia, and hydrocarbons—as well as lower-GWP synthetic alternatives like R32 and R454B.

§What it means for you as a refrigeration technician

In your career you'll meet both the old HFC systems that will still need servicing for years to come and a growing share of systems with natural refrigerants. This requires you to know more about different refrigerants' properties than previous generations of refrigeration technicians did and to adapt when a new refrigerant appears on the market. This is not a passing trend — it's the direction all legislation points.

“A low GWP number means the refrigerant is not necessarily safe — it only means it is friendly to the climate. Toxicity and flammability you must still respect every time.”