AC Refrigerant HFO-1234yf or simply R1234yf

Car manufacturers have been forced to change the refrigerant used in the air conditioning system from 2017 onwards. The EU has decided that the refrigerant used for the past 20 years is less environmentally friendly than a refrigerant with a lower Global Warming Potential (GWP). Initially the response was to use carbon dioxide gas (CO2) to cool the car. This is actually possible but resulted in very poor results in areas where the temperature is high, like the Sahara - exactly the sort of place where AC is required. This would result in more fuel being used to cool the car - not exactly what we would want nor would that be very environmentally desirable.

HFO-1234yf (pronounced as twelve, thirty-four y f) is the refrigerant chosen to achieve this object and more usually now referred to as R1234yf even though it is an HFO. Originally planned to start in 2011 the start date was delayed for 2 years because the supplies of this refrigerant were so restricted. Supplies of this R1234yf are now available but it is extremely expensive. Although expected to reduce in price eventually it is forecast to always be much more expensive than the existing refrigerant R134a. There is no requirement to convert cars built to run on R134a to use this new refrigerant, they may legally be recharged with R134a for the foreseeable future.
Since the first of January 2017 every new car must use this new refrigerant or another with a lower GWP than 1300 and also all slightly larger vehicles that have been completely redesigned. Additionally if originally built to use R1234yf the system must only ever be recharged with that refrigerant, by law, with huge penalties. Generally these cars new in 2017 should not require an AC service until about 2020, unless they have an accident though. However do be careful if buying a secondhand vehicle built after about 2013. All new models of cars which were a complete redesign after about 2013 were required by the EU to use this new refrigerant so it is quite possible to buy a newer car which may need an AC service soon - it may even have been the reason the previous owner wanted to pass on the car. There were completely new models produced as early as 2011 which used this new refrigerant but they were very rare in UK (Subaru XV was an example).
The body shop that repairs his car must ensure that the refrigerant in the AC system is carefully recovered before repairs to the AC system can be made and then accurately replaced so that on return to the owner the AC works as before. As this refrigerant is slightly flammable it may also be necessary to remove the refrigerant even if the AC system is not damaged before any other damage to the car can be resprayed as the car has to then go into a low-bake oven which with a refrigerant which is flammable may be potentially dangerous. Thatcham may require that. Although thought to be only lightly flammable, the law in the UK categorises R1234yf as an "Extremely Flammable Gas" - Class 2.1 on the Safety Data Sheets.
Many virtually brand new cars have to be repaired as a result of an accident in the first few weeks after purchase. Just be careful with that new car out there.

The HFO means that it is a Hydrofluoroolefin. If you want to win a pub quiz, it is 2,3,3,3,Tetrafluoropropene. A complicated chemical and no - I don't understand it either.
This HFO1234yf has been very controversial so far. All refrigerants have advantages and disadvantages and the trick is to achieve an acceptable balance. Usually it a question of balancing the efficiency and safety against the environmental acceptability. Some very efficient refrigerants with a low GWP are very flammable. R12 and R134a had similar boiling points, were not flammable at all, were extremely efficient but had environmental concerns. HFO1234yf has a low GWP and works like R134a but is very slightly flammable and this concerned some German car manufacturers, mostly Daimler-Benz who felt that this slight safety factor was more important than the environmental concerns. Although only slightly flammable it is possible for R1234yf to burn and Daimler were concerned that when it burnt in a moist environment (like a misty day) it had the potential to create some extremely nasty acids and misty mornings are quite common in Germany.
The EU stamped it's foot however and insisted that Mercedes observed the EU regulations. I am not sure that the German government forced their national manufacturers to comply with the EU regulations. The French government retaliated by refusing the import of the Mercedes cars that did not comply with EU regulations. The German government threatened the French government for restrictions in trade - the French Conseil d'Etat then lifted the ban..... Even Toyota announced that it was going to use R134a ("temporarily") instead of R1234yf amid safety concerns raised by its customers although Toyota found no safety concerns themselves. So for now we have R1234yf but maybe this augument is not yet entirely over. In March 2014 the EU's Joint Research Centre issued a statement that they were satisfied that there was no serious risk with the use of this refrigerant under normal conditions but Daimler was still not happy and is further investigating the use of AC systems powered by CO2 instead. In October 2015 Daimler issued a statement that they were going to use R1234yf but with a sophisticated system to douse any flames using the inert gas Argon. They still intend developing a reliable CO2 system in the future instead of R1234yf. In September 2016 Daimler Benz announced that a Mercedes S class was being fitted with a refrigerant of CO2 (R744) which also complies with this strict law.

The search for other refrigerant blends (mixtures of other refrigerants) goes on. The prestigious American SAE has been testing two other blends from other refrigerant manufacturers which appear to meet the requirements of the EU on GWP. Both of these two blends (R444A is called AC5 and R445A is called AC6) contain a quantity of R1234ze a close relative of R1234yf together with other carefully controlled refrigerants.

I am not sure that I am entirely convinced by the apparent need to move away from R134a but I am not a scientist and I am a bit of a sceptic anyway but that does not matter, the powers that be have decreed that we all have to move in this direction. I can see that there is a chance that cars built before the 2013 deadline and use R134a might retain their secondhand value better than later model cars with R1234yf. Additionally I would have thought that cars which use R1234yf might also have higher insurance costs too. I do admit to my scepticism in Information Pages

Costs for recharging with R1234yf are very much higher than for R134a or even R12, please see the page on Costs

For the workshop needing movement of this new refrigerant R1234yf, do not overlook the recovery (degassing) of this refrigerant. Firstly, this gas is flammable, secondly it is extremely expensive so all the refrigerant that can be recovered will reduce the final cost of the recharge - don't ever waste R1234yf.

On the next page are some other AC Technicians around the country


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