A2L is here—what you need to know
Starting in 2025, the US government will require newly-installed residential HVAC equipment systems to meet new Global Warming Potential (GWP) limits established by the EPA Technology Transition Final Rule.
What is a refrigerant?
A refrigerant is a compound typically found in either a gaseous or fluid state that can easily absorb and reject heat. HVAC systems use refrigerant to help transfer heat from the inside to the outside of a space or vice versa.
What is the A2L Refrigerant classification?
A2L is a refrigerant safety classification assigned by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). ASHRAE Standard 34 assigns an identifying reference letter and number to each refrigerant, which classifies the refrigerant according to the hazard involved in its use. The capital letter (A) designates a toxicity class. Refrigerants assigned an A have lower toxicity, while refrigerants assigned a B have higher toxicity.
The second and third digits of the ASHRAE safety classification (2L) represent the flammability classification of the refrigerant as assigned by ASHRAE Standard 34. There are three ASHRAE flammability classifications and one subclass. Those classifications are 1 (no flame propagation), 2 (lower flammability), and 3 (higher flammability). The subclass is 2L, mildly flammable.
Following the 2020 American Innovation and Manufacturing (AIM) Act passed by Congress and subsequently signed by President Trump, the Environmental Protection Agency (EPA) is no longer allowing usage of high-GWP refrigerants in certain applications.
Only systems using A2L refrigerants are being manufactured for Residential Air Conditioning and Heat Pumps as of January 1, 2025. This equipment can be sold through December 31, 2025 and individual components of the system (parts) can be sold after that for servicing existing systems. New installations from January 1, 2026 on will need to be designed for and utilizing A2L refrigerants.
A2L refrigerant cannot be used in systems not designed for those A2L refrigerant, nor is it possible to use A1 classified refrigerants in A2L equipment.
What is A2L and why should I care?
A2L is an HVAC refrigerant with similar characteristics to legacy refrigerants but is safer to use than ammonia and hydrocarbon refrigerants. It is more energy efficient than R-410A and replaces HFC and HCFC refrigerants. A2L refrigerants have lower flammability, so they are safer for handling and more stable for storage and transport. They are also eco friendly, given that they can reduce global warming potential (GWP) levels by up to 90 percent.
By 2030 
, traditional HFC and HCFC refrigerants will no longer be available.
What is the difference between A2L, A2, and A3 refrigerants?
A1 refrigerants, such as R-410A which was used in systems manufactured prior to January, 1,2025, have low toxicity and no flame propagation.
A2L refrigerants, such as R32 and R-454B which are used in system manufactured January 1, 2025 or later, have low toxicity and lower flammability.
A3 refrigerants, such as R-290 and R-600a which are found in refrigerators, have low toxicity but higher flammability.
What does global warming potential (GWP) have to do with my HVAC system?
GWP is a measure of the impact of a Refrigerant compared to Carbon Dioxide (CO2) For example, one pound of a greenhouse gas with a GWP of 700 has an impact on the climate that is 700 times stronger than one pound of CO2, which has a GWP of 1. The new refrigerants that equipment is designed to use have lower GWP values than legacy refrigerants.
Can A2L be added to my existing HVAC system?
No, equipment should only be used with the refrigerant for which it is designed.
How safe are A2L refrigerants?
It is more difficult to ignite A2L refrigerants and sustain a flame with A2L refrigerants than highly flammable refrigerants like HFCs.
How efficient are A2L refrigerants?
A2L refrigerants are up to 12 percent more efficient than comparable R-410A systems.
How often is A2L used in HVAC systems around the world?
A2L has been used in cars since 2017; more than 80 percent of new vehicles sold in the US today have an A2L refrigerant. To date, more than 230 million air conditioners in more than 130 countries using A2L refrigerants have been installed around the world.
What does A2L mean for equipment design?
Systems designed to use an A2L refrigerant will have sealed electrical components, and leak detection and mitigation parts included.
Are there different “flavors” or proprietary blends of A2L refrigerants?
There are no proprietary blends; however, some examples of A2L refrigerants include: R-32, R-454B, R-454A, R-454C, R-1234YF.