A2L Refrigerants: Everything You Need To Know

The transition to mildly flammable A2L refrigerants (such as 454B and R32) is occurring whether you’re onboard or not. Refrigerants’ global warming potential (GWP) is driving these changes. In this article we will cover the evolution of refrigerants, why the changes are occurring and the impact on HVAC equipment.

What Is Refrigerant?

Refrigerant is a fluid that runs through the lines of your HVAC system to cool warm air. It changes from liquid to gas during this process, then condenses back to a liquid to start the cycle again. Traditionally, refrigerants contained hydrochlorofluorocarbons (HCFCs) or hydrofluorocarbons (HFCs), which are potent greenhouse gases. Due to their high GWP, these substances are being phased out under regulations such as the American Innovation and Manufacturing (AIM) Act of 2020.

The Evolution of Refrigerants 

HVAC Technician

R22 : Initially, R22 was widely used in HVAC systems. However, it contained chlorine, which posed significant environmental risks. Chlorine reacts with ozone molecules, creating hydrochloric acid that damages the ozone layer, leading to the infamous ozone hole.

410A : The industry transitioned to 410A, a chlorine-free refrigerant, to address the ozone depletion issue. While 410A does not harm the ozone layer, a study came out roughly 5 years after the switch and said 410A was not escaping through the atmosphere. It was instead creating a greenhouse gas effect.

Current Transition to A2L Refrigerants

The industry needed a solution with low Global Warming Potential and no chlorine. In addition, California came out and set a maximum GWP threshold of 750 for refrigerants used in the state. (see last paragraph of this article for more on GWP) This pushes major manufactures of refrigerants to develop suitable alternatives.

The new A2L refrigerants, such as 454B and R32, fit this requirement. 454B will replace R-410A in new equipment. It has a lower GWP and similar pressures to R-410A, making it a viable alternative. However, it is slightly more flammable that R410-A which required a classification as “mildly flammable refrigerant” (A2L) introduces new challenges and costs.

A2L Refrigerant And Efficiency Regulations

With the “mildly flammable” classification, each piece of HVAC equipment will require a control board called a “Refrigerant Detection Sensor”. These separate control boards use sensors to detect refrigerant leaks and shut off the compressor, while also activating the fan to dissipate the refrigerant. This added safety feature will increases the cost of each piece of HVAC equipment.

Efficiency standards are also evolving as regulations change. Gone are the days of 6 SEER or 8 SEER systems. Now, depending on your location, standards like 14.2 SEER are common in the Midwest. This shift means larger coils, modulating two-stage compressors, and ECM motors, all contributing to rising equipment costs.

The Financial Impact 

Install of HVAC Equipment On Rooftop With A2L Refrigerant

The increased costs of new HVAC equipment due to A2L refrigerants and efficiency changes can be significant. It could get pretty ugly. This is going to drive those in our industry who have not had a maintenance mindset on equipment to change their mind pretty quick. Regular maintenance becomes crucial to extend the lifespan of existing equipment and avoid the higher costs associated with buying new systems.

Understanding GWP and A2L Refrigerants

GWP compares how much heat refrigerant traps in the atmosphere, to how much heat the same amount of carbon dioxide traps. This is measured over a specific time period, usually 100 years. This comparison results in a numerical value. CO2 has a GWP of 1.

If a refrigerant has a GWP of 750, it means that over 100 years, the refrigerant would trap 750 times more heat than CO2. By using GWP values, scientists and policymakers can evaluate the long-term impact of A2L refrigerants.


As the HVAC industry transitions to mildly flammable A2L refrigerants like 454B and R32, the costs of new equipment will rise. This increase is driven by the need for additional safety features and higher efficiency standards. To mitigate these costs, regular maintenance and a proactive approach to equipment care will become essential. If you have questions about A2L refrigerants reach out to us at sales@rasmech.com or give us a call at 800-237-3141.

preventative checklist blog cta