R-600a
Also known as: R600a, Isobutane, HC-600a, i-C4H10
Natural hydrocarbon refrigerant for household appliances and small commercial equipment. GWP of 3. A3 (highly flammable) classification limits use to purpose-built, charge-limited equipment.
R-600a (isobutane) is A3 classified — highly flammable. Equipment must be specifically designed for A3 refrigerants. Never service or charge isobutane systems without proper A3-rated equipment and procedures.
Regulatory Timeline
Greenfreeze initiative in Germany introduces hydrocarbon refrigerants in household appliances
Major European appliance manufacturers adopt R-600a for household refrigerators
EPA SNAP approval for R-600a in household refrigerators and freezers in the US
US appliance manufacturers accelerate R-600a adoption as AIM Act pressures R-134a alternatives
What R-600a (Isobutane) Is
R-600a (isobutane) is a natural hydrocarbon refrigerant with GWP of 3 and zero ODP. It has been the standard refrigerant in European household refrigerators and freezers since the mid-1990s, when the Greenfreeze initiative demonstrated that hydrocarbons could safely and efficiently replace CFCs in domestic appliances. European manufacturers including Liebherr, Bosch, and Whirlpool adopted isobutane broadly, and it is now used in the majority of household refrigerators manufactured globally outside North America.
US adoption lagged due to regulatory requirements and conservative appliance safety standards. EPA SNAP approval in 2011, combined with AIM Act pressure on R-134a (the previous US household appliance standard), has accelerated domestic adoption. US appliance manufacturers are transitioning to R-600a as the standard for new household refrigerators and freezers.
The A3 safety classification requires that isobutane appliances be specifically designed with hermetically sealed compressors (no service access for field refrigerant handling), minimum charge sizes, and designs that prevent refrigerant accumulation in potentially ignitable concentrations. The design controls, not field service procedures, manage the flammability risk in household appliances.