The truth about new automotive A/C refrigerant R1234YF

It’s time for a chill pill - literally - the new twelve-34 refrigerant is not going to burn you to death in hellfire … or is it?

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Here's the question that sparked this report off (see what I did there?):

"There's some kind of hullabaloo brewing over a new automotive refrigerant R1234yf, supposedly replacing the current R134a. I understand it's much more expensive, plus it's a flammable gas, unlike R134a, which won't burn. Do you have an opinion on this? Should we hold on to our old cars and boycott all new cars until this absurd situation is resolved?" - Mike


R1234yf or its profoundly more tongue-twisting proper chemistry name 2,3,3,3-tetrafluoropropene >> is replacing R134a (1,1,1,2-tetrafluouroethane), which replaced Freon-12 (dichlorodifluoromethae).

(Try saying all that, fast, with 12 beers on board.)

 Ozone-destroying   freon-12 (dichlorodifluoromethane) >>   yesterday

Ozone-destroying freon-12 (dichlorodifluoromethane) >> yesterday


In the olden days they used freon-12 which was awesome as a refrigerant but might as well have been Sarin gas as far as the ozone layer was concerned. It was also a pretty good propellant for aerosol cans.

Developed countries basically ditched Freon-12 in 1996, and developing countries boned it in 2010, and today dichlorodifluoromethane is only used as a flame suppressor in submarines and aircraft.

The refrigerant in your car right now is probably the R134a that’s been in common use for about 20 years. It’s about the same as Freon 12 as a refrigerant, but its effect on the ozone layer is insignificant. It doesn’t burn in most environments, either, and it’s non-toxic.

In fact it’s commonly used in those broncho-dilating puffers you see people with respiratory problems using, from time to time, like athsma sufferers. So: it’s pretty safe.

But it is very bad for greenhouse. It’s like 1300 times worse than CO2 when you calculate the Global Warming Potential against standard protocols.

The new refrigerant - let’s just call it Twelve-34 because I can’t be depended upon to get 2,3,3,3-tetrafluoropropene right more than twice in a single package - has a global warming potential less than 1. (Some organisations say it's 4 - in either case, it's orders of magnitude less than R134a.)

BOC's specs on R1234yf >>

Global Warming Potential for dummies: CO2 has a GWP of One. All other gasses are indexed in relation to that. Methane is 34. Nitrous oxide - one of the gasses that got the Monkey Spankers doing the whole Cool Hand Luke bit - is 298. Like that. The current refrigerant is pretty bad.

On climate change: Just a side-note, because I know you climate change deniers are revving up now: Climate change is real. It’s a very serious problem. Mankind is causing the problem. We need to fix it. You are allowed to be a climate change denier. Unfortunately, though, choosing to follow that path also makes you a scientifically illiterate Muppet. (It’s up to you. Just make the bed and lie in it. Hope that helps. Looking forward to the comments already.)

More on the shift to R134yf >>

 Not a Twelve-34 Benz fire...

Not a Twelve-34 Benz fire...


The new refrigerant - Twelve-34 - is more flammable than the current one, but Honeywell/DuPont, which makes the stuff, says it is:

“Very difficult to ignite with an electric spark.” - Honeywell/DuPont

More on Making R1234yf in the USA >>

Its autoignition temperature is 405 degrees C, which means it’s harder to burn than paper. In fact, the only way HoneyWell/DuPont could get it to burn was to mix it with compressor oil and pass it over plate hotter than 900 degrees C.

That’s hotter than most really hot exhausts.

Mercedes-Benz disagrees. Probably because they’re arseholes who want to delay spending the big bucks on the new refrigerant. Read more about why they're such arseholes, and their unrealistic test >>


But following up on the three-pointed swastika’s disagreement, the German Federal Motor Transport Authority (the KBA) did its own tests and concluded that Twelve-34 is more flammable than the current refrigerant but determined that Twelve-34:

“Poses no material risk to occupants.” - German KBA transport regulator

After three rounds of tests, the KBA found:

"No sufficient proof was found with the cars tested that would have hardened the suspicion of a serious danger as defined by the product safety law." - German KBA transport regulator

Among carmakers, Benz seems to be a lone voice with its knickers in a twist over Twelve-34.

See also:



However, if Twelve-34 does burn, that’s bad - because A) cars are jam-packed with stuff that just loves to burn, and B) when Twelve-34 burns it decomposes into some rather bad shit that a sane person would opt not to breathe, given the choice…

...toxic, corrosive shit like hydrogen fluoride (which is, like, gagging to become hydrofluoric acid) and also something called carbonyl fluoride - which is almost phosgene gas, and almost as bad for you. So that’s nice.

So, hydrogen fluoride is a gas, righ? You breathe it in, and it touches the wet sides of your throat and lungs, and turns to hydrofluoric acid, which is memory serves is the most corrosive acid.

And Phosgene was responsible for about 85 per cent of the 100,000 chemical warfare deaths in World War I.

So if you’re a conspiracy theorist with at best a lax relationship with the facts, it would be simplicity itself to paint Twelve-34 as a cobblestone on the road to hell on earth.



But my take on this - with my engineer’s hat on - is this:

Your car is already a massive rolling Molotov cocktail. It’s a pyromaniacal paradise. There’s heat, electricity, airflow and plenty of fuel - the actual fuel in the fuel tank and all the other supplemental fuel like the plastics surrounding you in the cabin. (Made of materials guaranteed to flash off toxic, corrosive shit that you simply should not breathe, in a fire.)

I don’t know what you might presume, but these materials are simply not selected for their fire-retardant or low-toxicity properties. The foam in the seat cushions, the dash - I mean, Jesus. If people only knew…

Just to put this in perspective: the reason you don’t see more people dying in vehicle fires is not because the composition of the cars themselves is selected carefully on the basis of fire suppression.

Cars burn like a bastard - they’re packed with apocalyptic crap - in fact, they are the pyromaniacal equivalent of the girl who can’t say ‘no’.

They’re gagging for it. They like it hot.


Face it: when you get in a car, you are already sitting in a gianormous fire bomb. It’s like getting all the ingredients for a cake together. It’s all there.

The reason so few people manage to bake this particular sponge, and die in vehicle fires is: robust systematic safeguards. It’s not because petrol - that gasoline in ‘Murica - is safe. That’s not it.

Petrol is some of the most dangerous stuff imaginable. And you are in closely-coupled systems with tremendous acquired energy - sharing that space with that dangerous stuff - every day.

And you EV nuts - get back in your box. Have you seen how well lithium-ion batteries burn? Spectacular.



Robust engineering is all that ensures the risk of catching fire is low - in both normal operation and in the aftermath of a collision. Except of course in a Ford. They don’t seem to give a crap about that, in opposition to the position taken by most other carmakers.

In the context of all that - I simply do not see this new refrigerant as a problem. And the benefit of Twelve-34 is crystal clear. Because climate change is real.

For air conditioning professionals in the trade it means buying additional equipment - because you’ll need to test which refrigerant is operating in the cars you service.

You’ll also need delivery systems for Twelve-34 that manage the (admittedly low) additional fire risk. And there are different lubricating oil requirements as well, for things like compressors. More on this for trade professionals >>

But aside from that, like most automotive technology - the wide implementation of Twelve-34 is going to occur under the radar. Your air conditioning in your car is going to function exactly the same, and I doubt they’ll be building additional burns units in the major hospitals around the world to compensate.

If you’re concerned about automotive safety, don’t obsess about Twelve-34.

Do this instead: Buy a five-star car. Pay attention that the cross traffic is stopped and giving way to you, before you proceed through intersections, and stop texting when you walk across the road. Because that’s where the big automotive safety gains are to be found.

Let the engineers manage these systematic risks - because, when it comes to that stuff, they save your life every day in the modern world.