A2Ls and Mixing Refrigerants: Addressing Supply Chain Issues

The past few months have been filled with turmoil for the Heating, Ventilation and air conditioning (HVAC) industry as supply chain issues have interfered with the rollout of new air-conditioning equipment that uses A2L refrigerants.

A key deadline within the U.S. Environmental Protection Agency’s (EPA) regulations for residential and light commercial air conditioning and heat pump systems is approaching, and the industry is struggling to keep up with the demand for one of the predominant A2L refrigerants required to meet the regulations.

On Jan. 1, 2026, it will no longer be legal to install HVAC systems using a refrigerant having a Global Warming Potential (GWP) greater than 700. As a result, distributors and installers have loaded up inventory with HVAC systems that use R-32 and R254B (the predominant A2L refrigerants) and are now beginning to install this equipment by the EPA deadline.

A Shortage of Necessary A2L Equipment

Manufacturers of the new HVAC systems have done a good job preparing for the transition to A2Ls. However, manufacturers of the R454B refrigerant and the canisters used to transport R454B and R32 refrigerants fell short in preparing for the increased demand for the A2L refrigerants.

The industry has been experiencing a shortage of the R454B refrigerant, but more importantly, has been dealing with a shortage of the A2L refrigerant canisters. This is important because these canisters are required by HVAC installers and service contractors to properly charge the HVAC systems.

HVAC systems come pre-charged with a set amount of refrigerant to make installation easier, but to correctly charge the system, contractors may need to remove or add some refrigerant. Without an A2L refrigerant canister to carry and transport the refrigerant, the contractors can’t complete this important step.

What about hydrofluorocarbon (HFC) refrigerant canisters? Unfortunately, these canisters have different connection port threads and cannot be used with A2L refrigerants.

One might also think that since there is no shortage of R32 refrigerant, that it can be used to top-off an R454B system – after all, they are both A2L refrigerants. Unfortunately, in almost all cases, you cannot mix them. All refrigerants have different chemical compositions and mixing them can lead to system damage including overheating, compressor damage or overall system failure.

The mixing of refrigerants can also result in lower energy efficiency, leading to decreased performance and increased operating costs. It is for these reasons that the mixing of refrigerants is prohibited, with limited exceptions.

Codes and Standards Addressing the Mixing of Refrigerants

The 2024 International Mechanical Code® (IMC) has new provisions addressing the mixing of refrigerants.

Refrigerants with different refrigerant designations (in this case R32 and R454B) can only be mixed in a system when it is permitted by the equipment manufacturer and when the resulting mixture does not change the refrigerant safety group (in this case A2Ls).

Likewise, the ASHRAE 15 standards only permit the mixing of refrigerants when it is allowed by the equipment manufacturer. However, due to the negative impacts of mixing two different refrigerant types, this practice is prohibited or otherwise discouraged.

To further assist industry professionals in their efforts to safely transition to A2L refrigerants, the Code Council has developed the A2L refrigerant “Hot Topics” page which can be found on our website, here.

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