Automotive manufacturers once treated refrigerant choice as a simple compliance checkbox: but that phase is coming to an end. With the EU’s revised F-gas Regulation (Reg. 2024/573) now locking in a steep phase-down of HFCs (Hydrofluorocarbons) towards an almost complete phase-out by 2050, the choice is shifting firmly toward natural and ultra-low global warming potential (GWP) refrigerants.
While the regulation text is more explicit around stationary AC and heat pumps, the direction is clear: synthetic F-gases are set to become progressively more restricted, costlier and more politically exposed.
So, what does this mean for OEMs?
For OEMs in the UK and EU alike, especially those building vehicles for export into Europe, EU policy is effectively setting the global benchmark. And with Great Britain’s own F-gas reforms likely to track the EU trajectory, short-term thinking risks expensive redesigns and regulatory dead-ends. The question is no longer “Which refrigerant gets us compliant today?” but “How can we create a refrigerant roadmap that will keep us competitive, future-proof and credible on climate over the next decade and beyond?”
In this blog, we will discuss the current industry status of various natural refrigerants, their technical implications, and how these can be implemented for long-term success.
What are natural refrigerants, and what options should you be aware of
Natural refrigerants are substances that already exist in nature and have zero ozone depletion potential, very low GWP (typically around 1), and no persistent breakdown products.
For vehicle AC and heat pumps, the two most relevant are R744 (CO₂) and R290 (propane). Let’s look a little closer at the advantages and challenges of these 2 options.
R744 (CO₂) is moving from niche to serious contender in vehicle AC and especially in EV heat pumps. After more than a decade of demo systems and the first production cars appearing around 2016, interest has spiked in the EV era because CO₂ can deliver both cabin cooling and very strong heating performance at low ambient temperatures, which is critical for battery and cabin thermal management without destroying range. It brings clear climate and regulatory advantages, including:
- GWP of 1
- no PFAS-type breakdown products
- and non-flammability and toxicity
But it isn’t a simple drop-in: CO₂ systems operate at much higher pressures (often approaching 100 bar on the high side), which demands pressure-rated compressors and gas coolers, thicker-walled pipework, specialised valves and robust safety devices. Transcritical cycle control is also more complex and highly sensitive to gas-cooler conditions, and workshops need new tools, procedures and training. For OEMs, R744 offers a compelling long-term pathway, but one that comes with a significant engineering and service transition.
R290 (propane) is already well established in stationary heat pumps and commercial refrigeration thanks to its ultra-low GWP and strong efficiency, and it’s now starting to appear in automotive research projects, pilots and early EV heat pump demonstrators. Thermodynamically it’s an attractive option: studies show R290 can outperform R134a (a common chemical refrigerant) and some HFOs, and it runs at pressures similar to or lower than conventional MAC refrigerants, which can ease some hardware demands compared with R744.
The critical catch is safety.
As a highly flammable A3 refrigerant, R290 brings strict charge limits, tight requirements on sealed components and pipe routing, and often the need for gas detection, isolation, ventilation and fail-safe control logic, all within the already crowded and crash-exposed vehicle environment. Compliance with ATEX and IEC standards adds further engineering and cost complexity, and public perceptions around “propane in vehicles” remain cautious. For now, R290 is best seen as a promising but more experimental path for vehicles, in contrast to R744, which is closer to mainstream deployment.
Ultimately, natural refrigerants aren’t “drop-in” replacements. They may be cleaner for the climate and environment, but they force OEMs to rethink system design and safety, rather than just swapping the gas and carrying on as usual.
From our perspective, this shift relies on system-level co-engineering: refrigerant choice is now intimately tied to architecture, safety case, packaging and software. Every decision must be carefully planned and considered to ensure all elements work together effectively in all vehicles.
How ready is the industry?
From a readiness standpoint, R744 and R290 sit at very different points on the adoption curve. CO₂ systems benefit from an emerging automotive supply chain for compressors, gas coolers and valves, plus real-world experience from several EV platforms that already use or are piloting R744 heat pumps, particularly in Europe. The main gaps now are economic and practical: early systems can be bulkier and more costly, and service networks need new tools and training to handle CO₂ safely and efficiently. R290, by contrast, is highly mature in stationary heat pumps and commercial refrigeration, with well-developed guidance on safe use, and automotive prototypes are starting to demonstrate strong efficiency and EV range benefits. But there is still no common mass-market standard for propane MAC in vehicles, the regulatory framework for flammable refrigerants is evolving and fragmented, and OEMs must navigate a sensitive perception and brand risk landscape. For OEMs, R744 looks like the near-term “safe bet” natural refrigerant for vehicles, while R290 represents a higher-reward, higher-risk play likely to emerge first in specific architectures or niche applications.
Strategic questions OEMs should be asking
- What is our refrigerant roadmap to 2035 and beyond?
- Are we staying on R1234yf for a while, or planning a staged move to R744 and/or R290 as F-gas quotas tighten and costs rise?
- Which refrigerant best fits each vehicle platform?
- High-volume passenger cars vs specialist off-highway or heavy-duty vehicles may justify different solutions, especially where flammability risk or service conditions differ.
- How does refrigerant choice integrate with our EV thermal strategy?
- Can one R744 or R290 heat-pump loop cover cabin, battery, power electronics and perhaps e-axle cooling, or is a multi-loop architecture more robust?
- What is our safety concept and how will we demonstrate it?
- For R744: high-pressure containment, fail-safe relief, service procedures.
- For R290: zoning, leak detection, ventilation, ignition source control and crash-worthiness.
- Are our supply chain and partners ready?
- Do our compressor, heat-exchanger and thermal module suppliers have validated R744 / R290 platforms, or will this trigger multi-year co-development?
- What about the aftermarket and service network?
- Tools, training, refrigerant handling, and clear procedures for workshops (including independent garages) will be critical – especially for flammable refrigerants.
- How will this impact total cost of ownership?
- Upfront cost of new hardware vs improved efficiency (especially in EVs, where better heat pump performance translates into more real-world range).
Looking forward
For OEMs, moving to natural refrigerants is as much a systems and organisational question as it is a fluid choice. Refrigerant strategy has to stay in lockstep with evolving EU F-gas milestones and MAC rules, while also remaining compliant across all target markets. Architecturally, platforms need to be checked for their ability to package larger, higher-pressure CO₂ gas coolers or safely zoned R290 circuits without major redesign.
Hardware robustness and safety margins must be revisited, including higher pressure ratings and fatigue considerations for R744 and minimal charges & segmented circuits for R290. Controls become more sophisticated too, from optimising transcritical CO₂ operation and coordinating cabin–battery–powertrain thermal management, through to integrating propane safety logic directly into the vehicle’s control architecture.
All of this sits on top of thorough hazard analysis, clear documentation for regulators and insurers, early investment in service tools and technician training, and careful customer communication that positions natural refrigerants as climate-friendly and future-proof, while being transparent about how risks are managed.