Refrigerant
Short answer · Updated 2026
A refrigerant is the working fluid in a refrigeration or air conditioning system. It absorbs heat as it evaporates and releases that heat as it condenses. The main families are CFCs, HCFCs and HFCs, and under EPA Section 608 they must be recovered, never vented.
A refrigerant is the working fluid of a refrigeration or air conditioning system: a substance chosen because it changes between liquid and vapor at useful temperatures and pressures. As it evaporates it absorbs heat from the space or process being cooled, and as it condenses it rejects that heat somewhere else. The compressor and metering device drive this cycle continuously, so a single charge of refrigerant does its job over and over rather than being consumed like a fuel.
Because the fluid is sealed inside the circuit, a healthy system should keep essentially the same charge for its entire service life. Refrigerant that goes missing has not been used up; it has escaped. That single fact underlies most of Section 608. The regulation treats refrigerant as something to be contained, captured, and returned to service or destruction, never released, because many refrigerants damage the upper atmosphere or trap heat when they escape.
Refrigerants are grouped into chemical families with very different environmental profiles, and the regulatory treatment follows the chemistry. Chlorine bearing families deplete stratospheric ozone, while later replacements avoid chlorine but can still be potent greenhouse gases. A technician certified under Section 608 is expected to know which family a refrigerant belongs to and what obligations attach to handling it, which is why the exam's Core section leans so heavily on this vocabulary.
Common questions
What does refrigerant mean?
Refrigerant means the fluid that carries heat through a cooling system, changing between liquid and vapor at useful temperatures and pressures. It is sealed in the system and is not consumed in normal operation.
What are refrigerants?
Refrigerants are the chemical fluids used in air conditioners, refrigerators, freezers and chillers. They come in families with different environmental profiles: CFCs, HCFCs, HFCs and newer low-GWP HFOs.
Does a system use up refrigerant?
No. A healthy sealed system keeps the same charge for its whole service life. Refrigerant that goes missing has leaked out, which is why leak rate and repair rules matter.
Do I need certification to handle refrigerant?
Yes. Section 608 requires EPA certification to service equipment that contains regulated refrigerants and to buy most refrigerant for stationary equipment.
Sources
- Venting prohibition and recovery rules: 40 CFR Part 82, Subpart F (Section 608).
- GWP values: IPCC Fourth Assessment Report as adopted in 40 CFR Part 84.
Related terms
| CFC (chlorofluorocarbon) | An early family of refrigerants containing chlorine, fluorine, and carbon, with severe ozone depletion effects. |
| HFC (hydrofluorocarbon) | A chlorine free refrigerant family that spares the ozone layer but can strongly trap heat in the atmosphere. |
| Recovery | Removing refrigerant from an appliance and storing it in an external container, without necessarily processing it. |
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