Are HFO Refrigerants Sustainable?

I was thinking about this very topic earlier today. As we all know HFC refrigerants are being phased down across the world. While we are still lagging behind within the United States we can be assured that HFC’s do not have much of a future. There are many states pushing their own individual legislation on HFCs as well as bills in the Senate and the House. We have seen it all before with CFCs and most recently HCFCs with the phase out of R-22 finalizing at the beginning of this year. It is something we have grown accustom too and something that many business owners have to adapt to.

There have been a few proposed solutions to replace popular HFC refrigerants such as R-404A, R-134a, R-410A, and R-507. The first is getting back to our roots and using classic refrigerants such as hydrocarbons, ammonia, or carbon dioxide. These refrigerants have all been tried and true and while they each have their own specific downsides it may be time to look at them again. Over the decades technology has improved these natural refrigerant systems. There aren’t as many failures in the high pressure carbon dioxide systems. There are more specific safety precautions and charge limits built into hydrocarbon systems. Best of all, these natural refrigerants are all nearly climate neutral. They have no Ozone Depletion Potential and very low Global Warming Potential. The obvious downsides is that they can be expensive when compared to artificial refrigerant systems and there is also the flammability, toxicity, and high pressure risks.

The other proposed solution and one which is taking on steam right now are the new classification of refrigerants known as Hydrofluoroolefins, or HFOs. These HFO refrigerants are synthetic refrigerants just like their HFC predecessors. The difference is that the HFO refrigerants are more environmentally friendly then the very high Global Warming Potential HFC refrigerants. One of the most successful HFC to HFO switchovers can be found in the automotive market. Rewind about six or seven years and every vehicle was using the HFC R-134a. 134a has a GWP of one-thousand four-hundred and thirty. Around 2014/2015 vehicle manufacturers begin switching their new models away from HFC 134a and over to the newer HFO known as 1234yf. This yf refrigerant has a GWP number of only four. That is a huge difference between the two refrigerants.

The Global Warming Potential scale is a measurement of how much impact a specific gas has on the environment, or more specifically on global warming. The common HFC refrigerants we use today are known as ‘Greenhouse Gases,’ or ‘Super Polluters.’ These gases contribute a significant amount to the warming of the planet, more so then standard carbon dioxide. In fact the GWP scale is based off of carbon dioxide, or R-744. R-744’s GWP is one. So, any gas that has a GWP number greater then one can be seen as harmful to the environment. This is precisely why we are seeing the phase down of HFC refrigerants across the globe.

Now we know that there are no perfect refrigerants and alternatives to HFCs are still going to measure on the GWP scale. It is now just a question of how much? In the example we gave above on automotive applications we saw that switching from R-134a over to R-1234yf we were able to shrink the GWP number by over one-thousand fourteen-hundred. That is a significant amount and I can see the HFO R-1234yf being used in cars in the distant future. This is what we want to see when moving applications away from HFCs and over to HFOs.

The question now though, and the reason I am writing this article, is what to do when a new alternative HFO refrigerant is suggested or used even though that new refrigerant still have a high GWP? Earlier today I was reading an article on how the National Hockey League has been transitioning their ice rinks away from their older R-22 or R-507 systems and over to a newer HFO refrigerant known as R-449A (Under the brand name of Opteon XP40).

This is all well and good but when I looked at the GWP of R-449A I was quite surprised. This HFO refrigerant has a GWP measurement of one-thousand four-hundred and forty-nine. That is NOT a low number. While, yes, it is significantly lower then R-404A and R-507 it is still high. Let us look at a few numbers here. R-404A and R-507 has a GWP of nearly four-thousand. By switching away from these HFC refrigerants and over to R-449A there has been significant impact on the environment. However, if we look at switching from an old R-22 system over to R-449A there is much less of a savings. R-22 has a GWP of around eighteen-hundred. The difference here is that when switching over to R-449A you are removing the Ozone Depletion Potential risk that you have with R-22.

My concern is for the businesses that are investing in these all new machines with HFO refrigerants. In the example of the article I mentioned above, lets say that an ice rink retired their old R-22 system and installed a new HFO R-449A system. While they are reducing their environmental footprint at the time what happens in the future when it is decided that refrigerants with a GWP of over one-thousand are no longer suitable? Or, let us go even stricter and say that refrigerants with GWP of no higher then five-hundred? Stricter regulations and laws are always being introduced on refrigerants and I just do not see it making sense to investing in a whole new system only to have it deemed as environmentally harmful in five, ten, or fifteen years later.

Now, I am not saying all HFO refrigerants are like this. There are many that have very low GWP just like the 1234yf that we had mentioned earlier. The question on my mind though is should businesses really be looking at these HFO refrigerants that come with a high GWP? If it was me then I would only look at the HFOs with a high GWP if I am aiming to retrofit my existing system away from an even higher GWP refrigerant. If instead I am looking to purchase a whole new system then I would either go with a natural refrigerant or with an HFO refrigerant that has a very low GWP number. This would significantly reduce risk of another phase out on the refrigerant you selected.


The table above shows the various HFO refrigerants out there and their related Global Warming Potential number. You’ll notice that more then half of them have a GWP of over five-hundred. How long will these refrigerants be around? Will they be sustainable in the future? Or, will they end up biting the dust just like CFCs, HCFCs, and now HFCs?