The shift to A2L gases will affect air conditioning systems, heat pumps, chillers, and commercial refrigeration units. As manufacturers update existing product lines to utilize A2Ls, the focus is not only on refrigerant compatibility, but also on improving system performance and reliability.  

Implementation Challenges 

One of the main challenges with A2L refrigerants is that they are mildly flammable. This new challenge requires that manufacturers adapt their designs and conduct rigorous testing to ensure that HVAC systems are safe under all expected operating conditions. 

For starters, HVAC systems require design modifications to ensure compatibility and safety. All system components, including compressors, heat exchangers, and expansion devices, must be rated for A2L refrigerants. Failure to use appropriate components could lead to operational inefficiencies or increased safety risks. 

To mitigate flammability risks, HVAC systems using A2L refrigerants must be able to detect refrigerant leaks and take mitigating actions to ensure the refrigerant concentrations do not reach a hazardous level. To provide this capability, systems are equipped with advanced safety features and control logic, including integrated leak detection sensors and ventilation controls. There are many A2L leak detection sensors on the market, and OEMs are encouraged to select sensors that employ proven technology and offer sustained performance for many years to come. 

In the world of A2L leak detection sensors, cheaper is often not better. Given the criticality and advanced functionality of some sensors, OEMs can effectively and quickly manage fan and compressor mitigation actions via the sensor itself. This advanced functionality provides substantial savings over adding new control capabilities to existing system control boards. With such advanced sensors, equipment manufacturers may choose to think differently about their A2L control strategies as they balance control and sensing requirements.  

Installation And Service 

Installing A2L refrigerant systems is usually like installing R-410A units; however, technicians should always check the manufacturer’s installation instructions for each system. The main difference between the two systems is in the wiring, which varies depending on how the manufacturer designed the system to handle refrigerant leaks. Some manufacturers have elected to use their proprietary control boards to manage leak responses, while others rely on sensors to act as an intermediary device. On average, installing an A2L system takes about 30 minutes longer than a traditional system because of the extra care needed in wiring.  

When servicing these systems, it’s important to understand how leak mitigation works in each unit. Since sensors are a key part of an A2L-based system, technicians must accurately diagnose problems. In general, maintenance of an A2L system is approximately the same as what is done for R-410A units. The only difference is that OEMs may recommend checking to make sure that the A2L sensor is free of dust and debris and that the sensor is operating properly. This is usually easy to do via a visual inspection -- observing an indicator light or other visual cue -- which should be added to a technician’s checklist. 

If a sensor is determined to be faulty, it must be replaced with the exact same model from the same manufacturer. Sensors of a different model or from different suppliers may look identical to each other, but their function may differ substantially. This is due to the software that is utilized inside the sensor and determines when a leak is present or how that sensor responds to a leak. It is important that technicians do not make unapproved substitutions, as this could reduce or otherwise compromise the effectiveness of the system’s safety features. 

The shift to A2L refrigerants is one of the most significant changes the HVACR industry has faced in recent years. While the transition presents challenges, it also offers an opportunity to improve the energy efficiency, safety, and sustainability of HVAC systems. Companies like Danfoss are playing a key role in developing the necessary technologies to support this transition, from advanced sensors to innovative components that make A2L systems safer, more efficient, and more reliable. With the approaching 2026 deadline for commercial refrigeration systems to switch to A2Ls and other low-GWP refrigerants, the future of HVACR looks more sustainable and more connected than ever.