A new report from the Environmental Investigation Agency (EIA) US highlights a pathway for opening the US residential and commercial HVAC market to hydrocarbon refrigerants such as propane (R-290), citing their ultra-low global warming potential (GWP) and high efficiency. The briefing calls for aligning US safety standards with international norms to enable broader use of hydrocarbons in air conditioning and heat pump (AC/HP) systems between 2030 and 2035.
Hydrocarbon refrigerants like R-290, with GWPs under 10, are already gaining traction globally, especially in Europe. However, their use in the US is restricted by outdated safety codes and charge size limitations. The report identifies harmonization of two key US standards—UL 60335-2-40 and ASHRAE 15—with IEC 60335-2-40 as a necessary step to allow R-290 adoption in most central AC and heat pump units.
Technical analysis suggests that full harmonization could allow 78–88% of new US AC/HP sales to transition to hydrocarbon refrigerants, depending on system efficiency and installation parameters. This includes ducted and mini-split systems, which make up the majority of the US market. Expanded safety research is already underway and should inform upcoming revisions to UL and ASHRAE standards, with proposals expected by 2027 to meet the 2030 model building code cycle.
Case studies from Latin America, including R-290 ducted split and rooftop systems by Thermotar, show that propane-based systems can be safely designed for capacities up to 60,000 BTU/h with less than 1 kg of refrigerant. These units incorporate leak detection, sealed electrical components, and pump-down mechanisms to meet safety requirements. While currently more expensive than A2L-based systems, they offer up to 30% higher energy efficiency.
“Full harmonization with IEC 60335-2-40 is a realistic path to enable a vast majority of newly manufactured US air conditioners and heat pumps to use R-290 and other ultra-low GWP A3 refrigerants nationwide,” the report concludes.
The EIA calls for broad stakeholder engagement in UL and ASHRAE technical committees, as well as increased investment in safety testing for a wider range of equipment types to ensure comprehensive market readiness.
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