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Natural Refrigerant Heat Pumps: A Sustainable Solution 

Natural Refrigerant Heat Pumps: A Sustainable Solution 


As the world continues to grapple with the challenges associated with climate change, the need for sustainable, energy-efficient solutions has never been greater.

Modern heating technologies relying on F-gases like HFCs may help towards more energy efficient solutions, but they contribute significantly to global warming due to their high Global Warming Potential (GWP). This is why we are seeing a gradual shift to natural refrigerant heat pumps, a proven environmentally friendly alternative that combines high performance with a drastically reduced carbon footprint. 

The Environmental Case for Natural Refrigerants 

Natural refrigerants refer to those which are naturally occurring, such as propane, ammonia or carbon dioxide, and when it comes to combating climate change, the environmental cost of refrigerants cannot be underestimated. F-gases, such as HFCs, are widely used in traditional heating and cooling systems but have alarmingly high GWP, when those gases are released into the atmosphere, they trap significantly more heat than Carbon dioxide, which leads to the acceleration and worsening of global warming.  

Natural refrigerants, in contrast, have a much lower GWP. This stark difference makes natural refrigerants an obvious choice for environmentally conscious projects, especially with the increasing regulations aiming to minimise high-GWP refrigerants. 

Large F-gas systems are also known for leaking 5–10% of their refrigerant into the atmosphere annually. These leaks, categorised as ‘fugitive emissions’, significantly increase the carbon footprint of a building and must be reported under PAS2050 carbon reporting; by making the use of low-GWP refrigerants it’s also an effective way to reduce reported emissions. 

By adopting natural refrigerants such as R744, R290, or R717, building systems can drastically reduce their environmental impact, aligning with carbon reduction targets and creating a more sustainable future. 

Photo by Clade Engineering

Key Benefits of Natural Refrigerants

Natural refrigerant heat pumps have an array of benefits that make them an increasingly popular choice for both new builds and retrofit projects. Their superior operational performance, compatibility with existing systems, and alignment with future environmental regulations set them apart from traditional F-gas systems, whilst being significantly better for the environment. Major benefits of natural refrigerants include: 

  • High Efficiency at High Temperatures – Natural refrigerants like R744 (CO₂) and R290 (propane) can deliver LTHW at 65–80°C with excellent SCOPs. Unlike some common systems being specified today in UK building services which rely on HFC’s, heat pumps using natural refrigerants often don’t require additional in-line equipment to boost temperatures for DHW, cutting capex and operational costs!  
  • Cost-Effective Retrofits – For refurbishment projects, R290 systems often work with existing radiators and pipework, due to their ability to operate at a more traditional system ΔT, matching those of gas boiler led systems minimising upgrades and reducing installation costs. Reusing infrastructure also lowers the whole-life carbon impact of the project. 
  • Reduced System Costs – While some systems (for example R744) may have higher capex costs for the heat pumps themselves compared to their competitors, savings from smaller-diameter pipes and simpler installations make natural refrigerants more cost-effective over the system’s lifespan. This is due to the wider system ΔT that is required (around 40°C) which reduces the mass flowrate of the systems, thus reducing pipe sizes, valve sizes, simplifying installation and reducing the embodied carbon of the MEP package.  
  • Future Proofing and Compliance – Natural refrigerants meet tightening regulations like the UK’s 79% F-gas reduction by 2030. They ensure long-term compliance, reduce reliance on HFCs, and enhance sustainability credentials, supporting net-zero goals. 

There is also a significant push from consumers and industries for more sustainable alternatives. Natural refrigerants align with the needs of conscious companies, stakeholders and consumers striving to reduce their carbon footprint.  

For businesses, adopting a low-GWP refrigerant system can increase the marketability of assets. Buildings with sustainable heating systems are more attractive to potential renters and buyers who prioritise green initiatives, making them valuable in competitive markets. This trend also reflects growing consumer and corporate demand for solutions that align with modern ESG targets and climate-driven goals.

Photo by Clade Engineering

Looking Ahead

As industry continues to evolve, natural refrigerants are emerging as the leading alternative to F-gases. Manufacturers are increasingly developing next-generation heat pumps which utilise natural refrigerants. By using these systems now, businesses can stay ahead of production trends and position themselves as leaders in sustainable innovation. 

Additionally, there are tightening regulations which are accelerating the shift away from F-gases. Following Brexit, the UK adopted and rebranded the EU’s F-Gas regulations to DEFRA F-Gas regulations which mandate a 79% reduction in F-Gases by 2030. The UK is also committed to reducing HFCs by 80% by 2047 under the international treaty, the Montreal Protocol. Additionally, the Green Heat Network Fund offers financial incentives to projects using low-GWP refrigerants. These measures collectively push for a lower-GWP future. 

Although natural refrigerants are not a new discovery, their application in heat pumps has only gained momentum in recent years. Industries like retail and logistics have long relied on ammonia, propane, and CO₂ in large-scale refrigeration systems. Think of shops like ASDA and Tesco, where these refrigerants have been safely used for decades. The challenge, however, lies in applying this technology to domestic and commercial heat pumps. 

Natural refrigerants present some manageable challenges, each of which can be addressed with proper safety measures and protocols. Propane (R290) is flammable but is used in minimal quantities, comparable to the amount of propane found in a typical barbecue. BS EN 378 helps us navigate these challenges with ease. CO₂ (R744) operates at high pressures, which can increase manufacturing costs; however, its efficiency offsets these costs by reducing the capex required for pipes, valves, and installation, as well as opex. Ammonia (R717) is toxic at high concentrations, but it is safe when stored and managed correctly with appropriate controls. These risks are well understood and can be effectively mitigated through proper management protocols, robust safety measures, and training. 

Photo by Clade Engineering

With increasing regulatory pressure, evolving manufacturer offerings, and consumer demand for sustainable solutions, natural refrigerants represent a critical investment for the future. By adopting these technologies early, businesses can reduce environmental impact, stay compliant, and deliver systems that align with net-zero and ESG goals. 


To connect with our MEP team to discover how we can help your business meet its ESG goals and implement more sustainable solutions get in touch.