Retrofits to return: Why it won’t be simple

Chemours and Honeywell have announced the development of a “retrofit approach for vehicles using the legacy R134a mobile air-conditioning refrigerant” that enables these systems to run R1234yf.

As Honeywell rightly points out, there are hundreds of millions of cars on the roads “potentially leaking R134a every day.”  

Replacing all that refrigerant, with its global warming potential (GWP) of 1430, with an almost zero-GWP alternative would undoubtedly be a triumph in the battle to get climate change under control.  

But let’s not get ahead of ourselves. At the moment this announcement is little more than a proposal.  

In the United States and other regions that place a high value on US Environmental Protection Agency (EPA) rules, it requires input and acceptance from SAE International, which developed a raft of standards for YF systems owing to the refrigerant’s A2L mild flammability rating, regulatory approval in various jurisdictions around the world and buy-in from vehicle manufacturers (and likely their suppliers of air-conditioning system components).  

Honeywell’s advertised five-step procedure (pictured above opposite) includes the installation of new permanent service ports, use of a special PAG oil, and attaching labels to indicate that a refrigerant retrofit has been done.  

Not included in the process is the purchase of, and training in, equipment suitable for R1234yf once it is time to charge the system.  

As has been covered in several past editions of SightGlass, there are millions of cars out there with systems that meet R1234yf criteria but were charged with R134a for sale in markets where regulations allowed them to (such as Australasia).  

These vehicles would mostly have been manufactured from 2017 onwards when the European Union mandated the use of refrigerants with a GWP of 150 or less in all new light vehicles.  

Newly type-approved light vehicles – i.e. generational changes on new platforms – had to ditch R134a from the start of 2013.  

In the United States, R134a was supposed to be banned from light vehicles for the 2021 model year but legal battles pushed this out to 2025. However, for some time US corporate average fuel economy (CAFE) regulations have incentivised vehicle manufacturers to make the switch by essentially improving a model’s miles per gallon rating (therefore carbon footprint) if it has a low-GWP refrigerant.  

Fiat Chrysler Automobiles jumped on this opportunity first, in late 2013, with Cadillac similarly early before other General Motors brands joined by the end of 2016 – the year when Ford only just started the switch.  

Vehicles produced under either of these regimes – provided there was no reasonable doubt about the system’s compliance with standards relevant to R1234yf use – a retrofit would theoretically be straightforward.

Then again, retrofitting R134a systems designed without R1234yf in mind is increasingly considered to be safe.

However, Honeywell’s literature on the matter – seemingly aimed at the European market given its reference to EU F-Gas regulations – says “the process to retrofit older R134a cars with R1234yf is the simplest, most reliable and best-performing repair option available”.

“There are over 200 million cars on European roads potentially leaking R134a every day that could be safely converted to near-zero GWP R1234yf refrigerant,” it continues.  

Chemours seems to have taken a more global outlook with its statement.  

“While many countries have transitioned to lower GWP refrigerant technologies, millions of vehicles remain on the road using R134a,” said the company’s senior technology director, Amber Stephenson.  

“Developing a safe, simple, and cost-effective retrofit approach to facilitate the transition to low GWP technology is a critical step forward.”

However, SightGlass understands that Chemours rushed out a statement on R1234yf retrofits as it had been somewhat blind-sided by Honeywell’s announcement.

Honeywell is also casting its net beyond Europe. The US EPA Significant New Alternatives Policy (SNAP) program received an application last year for approval to offer YF as a retrofit for existing R134a systems.  

As VASA’s North American counterpart MACS points out, “EPA SNAP approval is not a fast process … It takes one to two years to complete before any approval or denial is issued.”

Hybrid and electric cars not included

Former MACS president and consulting industry advocate Peter Coll pointed out to SightGlass, Honeywell’s SNAP application is restricted to passenger cars and light trucks with a mechanical compressor but does not request approval for other vehicle classes or those with an electric compressor such as EVs and various types of hybrid.

If R1234yf retrofits are approved, the EPA would stipulate that they are only carried out on cars and light trucks with a mechanical compressor.

Coll considers the introduction of R1234yf and R456A retrofits for R134a systems as aimed at global markets.

Electrified vehicles with heat pumps also need refrigerants that can both cool and heat passenger compartments, batteries and driveline components efficiently, while meeting low-GWP requirements and not impacting battery range too severely while in operation.

This was a major topic of the SAE’s Thermal Management Systems Symposium that took place in Detroit at the beginning of October this year.

Regulation, safety and manufacturer approval

While the environmental benefits of transitioning to R1234yf are clear from a GWP perspective, the regulatory landscape is complex and varies across regions – but it is the potential for auto-makers to have their own rules around which models are approved for retrofits and the equipment used to do so.

In the US, the EPA and SAE will play crucial roles, but Coll explained that the path to making retrofits a reality involves multiple stages.

The first step toward regulatory acceptance involves approval from the EPA’s SNAP program, a rigorous process according to Coll.

First, a formal application – as already submitted by Honeywell – must include data on safety, environmental impact, and compliance with existing laws. Once this is submitted, the EPA issues a “letter of completeness” or “incompleteness.” In most cases, the latter requires additional data submission before the EPA can proceed with reviewing the retrofit proposal.

If and when the application reaches completion, a Notice of Proposed Rulemaking (NPRM) is issued, opening the floor to public and industry feedback. This is followed by a 30-day consultation period, during which stakeholders have the opportunity to voice concerns or suggest changes. 

Coll said the entire process, from submission to approval, typically spans 1-2 years.

For Europe, the regulatory pathway is quite different. EU regulations mandate refrigerants with a GWP lower than 150, meaning R1234yf qualifies on paper but the idea of retrofitting systems designed for non-flammable A1 refrigerant with a ‘mild-flammability’ A2L alternative has triggered safety concerns, especially regarding retrofitting older systems designed for non-flammable R134a

MAC Partners Europe president and Nissens Automotive global technical training manager Michael Ingvardsen told SightGlass the safety and liability concerns car-makers must consider could be difficult to overcome – especially with Mercedes-Benz, which famously opposed R1234yf citing flammability as its major objection. 

According to Ingvardsen, insurance costs and the risk of potential fires, no matter how low, loom large over the debate.

In addition, environmental concerns surrounding R1234yf’s impact on PFAS and TFA levels have been raised in several European countries, including Denmark and Germany. 

These concerns could ultimately lead to the phase-out of R1234yf in Europe, potentially making alternative refrigerants such as R444A and R456A more attractive options. However, the impact of PFAS concentrations in relation to R1234yf is still not well understood and is currently being investigated by various authorities around the world.

As was the case with the transition from R12 to R134a, each car-maker will have to assess which vehicles can be safely and economically retrofitted. SAE approval does not automatically mean auto-makers will follow suit.

Liability concerns will be top of mind, especially in Europe, where Ingvardsen suggests many car-makers and their component suppliers could remain resistant to retrofitting vehicles not previously tested with R1234yf due to the risk of legal repercussions should a fire or other incident occur.

Exacerbating this cautious approach is lingering frustration among European automotive manufacturers over the way R1234yf was introduced, without the sufficient input from them, a level of discontent Ingvardsen expects to impact the reception of this retrofit proposal in Europe.

Coll explained that while the EPA may approve R1234yf for retrofits, individual manufacturers will need to determine model-specific guidelines, although he expects this to only apply to dealer networks.

He said there would likely be conditions around the use of servicing equipment meeting SAE J2843 or J3030 as these have vacuum and pressure decay testing capabilities to ensure integrity of the system being retrofitted, as well as a J2843-compliant recovery unit if R1234yf is to be reclaimed for safe disposal or on-site recycling.

Ingvardsen said this was not the case in Europe, outside the jurisdiction of SAE standards, and that while much of the equipment sold there is designed for global markets including the US and therefore meets J2843, the standard is not fully implemented in practice.

Alternatives to R1234yf

While R1234yf remains the focus of this retrofit proposal and Coll expects it to be approved with use conditions as a retrofit for certain automotive applications, it is by no means the only option on the table.

Refrigerants such as R456A, with its non-flammable A1 classification and lower GWP, may offer a more palatable alternative in regions where flammability and PFAS concerns dominate the conversation.

Coll also expects this alternative to be accepted – in the US at least – but pointed out that the availability of service equipment for R456A is currently limited, which could hamper its adoption in the short term, not to mention the fact its GWP of 656 could rule it out for jurisdictions like the EU which mandate a GWP of 150 or lower.

In Europe, Ingvardsen has seen R444A emerging as a viable alternative, offering lower PFAS/TFA levels than R1234yf plus a GWP of 92, therefore aligning better with some of the EU’s more stringent environmental standards.

On these grounds, he sees the existence of R444A as making it harder for R1234yf to be approved in Europe because R444A ticks so many more of the EU’s environmental boxes than R1234yf.

Coll said R513A (GWP 573) had been considered for mobile air-conditioning applications but is no longer a candidate due to potential performance and servicing issues.

Some industry players are concerned that blends such 444A and 456A could present servicing and even operating challenges, especially in mobile applications, due to glide (the temperature difference at a given pressure whereby the components of the blend change phase).

Glide could also result in the refrigerant more easily falling out of specification in the event of  leak, making re-use more difficult and therefore likely less frequent, as well as  potentially impacting the use of all-in-one Recovery/Recycling/Recharging machines for service.

Is it safe?

Automotive air-conditioning systems designed for R1234yf are supposed to meet SAE standard J2842 regarding evaporator construction, with connections and TX valve located outside of the passenger compartment. Vehicles predating this standard are unlikely to include these safeguards.

However, Coll said the J2842 evaporator rule was put in place “due to an overabundance of risk mitigation” due to the fact a mildly flammable refrigerant had never before been used in production mobile systems.

He added that the reality was that all R1234yf performance and safety testing was done on R-134a vehicles, well before R1234yf was introduced. 

“Furthermore, the R1234yf Cooperative Research Program Risk assessment #4, done after the Daimler fire concerns were raised, reaffirmed that R1234yf could be safely used in existing R134a vehicles, even those without the new evaporator certifications,” he explained.

Coll expects the US EPA to require non-removable R1234yf service ports to be installed as part of the use conditions for R1234yf or any other SNAP-approved R134a retrofit refrigerant such as R456A.  

“These service port fittings are already designed and would be available when R1234yf is approved for use,” he said.

What happens next

As the global automotive industry grapples with the phase-down of R134a, the introduction of retrofit options like R1234yf is seen as a critical step forward, especially as import and production quotas are reducing the availability of R134a for service while pushing up prices.

This will eventually lead to a refrigerant crunch, especially in markets like Australia where the quota system began without equipment bans, allowing vehicles and other equipment charged with high-GWP refrigerants to be sold into a market that will one day be unable to economically service and repair them using the original refrigerant.

It means time is ticking to overcome a set of significant hurdles for retrofits to become reality.

“As HFC restrictions take hold around the world per the Kigali agreement, there is a fear that R134a may be in short supply and expensive,” explained Coll.

“Having options that have been properly vetted gives the market a path forward if these conditions materialise. For regions where the price or supply is not a driver, the use of R1234yf, and to a lesser extent, R456A, offer a replacement with a dramatically lower global warming potential, which will benefit the environment.”

Regulatory approval, particularly from the EPA in the US and environmental agencies in Europe, will be essential, as will the support of car-makers and the broader industry.

The transition is further complicated by the ongoing search for refrigerants that offer lower environmental risks and fewer safety concerns.

While R1234yf is positioned as the leading option, the emergence of alternatives like R456A and R444A could alter the trajectory of the retrofit landscape, particularly in Europe if PFAS/TFA are prioritised over climate change.

Coll said Koura is awaiting its Notice of Completeness from the EPA for its application to SNAP approval of R456A.

As Ingvardsen put it, “The industry has become way more political and environmentally focused”.

This focus will shape the future of refrigerants, as car-makers, refrigerant manufacturers and regulators seek ways of balancing safety, cost and environmental impact.

For now, the proposals to retrofit R134a systems with R1234yf or anything else remain just that – a proposal.