UL standard harmonized with the international IEC standard covering the safety of electrical heat pumps, air conditioners, and dehumidifiers, including those using mildly flammable A2L refrigerants. It addresses ignition risk, refrigerant concentration limits, and safeguards specific to flammable refrigerant containment.
HVAC Glossary
UL 60335-2-40
Last updated: June 9, 2026