HVAC Reference Library · Refrigerants & Oils
Master Guide to Refrigerants
The common HVAC/R refrigerants: their chemical class, ASHRAE 34 safety group, typical applications and the federal rules that control their sale and use. It gives no pressure-temperature values.
Safety-critical sheet, not yet signed off by an expert reviewer. Use it to understand the topic, then take every value and decision from the governing standard, the manufacturer’s instructions and a qualified person.
What it is
A refrigerant is the working fluid that carries heat in a vapor-compression system. Refrigerants are named with an "R-" number under ASHRAE Standard 34. ASHRAE 34 also gives each one a safety group: a letter for toxicity (A = lower, B = higher) and a number for flammability (1 = no flame propagation, 2L = mildly flammable, 2 = flammable, 3 = highly flammable). Federal rules restrict who may buy refrigerants (40 CFR 82 Subpart F, Section 608) and which refrigerants new equipment may use (40 CFR 84, AIM Act technology transitions).
How to identify
- Equipment nameplate: shows the refrigerant type and factory charge. This is the first source to check.
- Container label: shows the R-number, safety group and hazard statements. Under AHRI Guideline N, containers are no longer color-coded by refrigerant, so identify by the label, never by cylinder color. Containers of flammable (A2L and A3) refrigerants carry a red marking, and some use different valve threads that need their own adapters.
- Unknown system charge: use a refrigerant identifier (analyzer). Do not guess from pressures.
Common refrigerants
| Refrigerant | Class | ASHRAE 34 safety group | Typical application | Status note |
|---|---|---|---|---|
| R-22 | HCFC | A1 | Legacy residential and commercial AC | Production ended; service from recovered or reclaimed supply |
| R-410A | HFC blend | A1 | Residential and light commercial AC and heat pumps | Being phased out of new equipment under 40 CFR 84 |
| R-32 | HFC | A2L | Ductless and new residential AC | Lower-GWP replacement |
| R-454B | HFO/HFC blend | A2L | New residential and light commercial AC | Lower-GWP replacement for R-410A |
| R-134a | HFC | A1 | Chillers, medium-temperature refrigeration, automotive (older) | Restricted in many new uses |
| R-1234yf | HFO | A2L | Automotive AC | Lower-GWP mobile refrigerant |
| R-1234ze(E) | HFO | A2L | Chillers, some commercial | Lower-GWP |
| R-513A | HFO/HFC blend | A1 | R-134a alternative in chillers and refrigeration | |
| R-404A | HFC blend | A1 | Low- and medium-temperature commercial refrigeration | Restricted in many new uses |
| R-448A / R-449A | HFO/HFC blends | A1 | R-404A retrofits and new refrigeration | |
| R-290 (propane) | Hydrocarbon | A3 | Self-contained commercial and domestic refrigeration | Highly flammable; charge limits apply |
| R-744 (CO₂) | Natural | A1 | Transcritical commercial refrigeration | Very high operating pressures |
| R-717 (ammonia) | Natural | B2L | Industrial refrigeration | Toxic; specialized handling |
Key points
- Do not mix refrigerants or "top off" a system with a different refrigerant. Use only refrigerants and procedures approved by the equipment manufacturer.
- Zeotropic blends (400-series, such as R-410A, R-454B and R-448A) must be charged as liquid to avoid fractionation.
- A2L refrigerants need A2L-rated equipment, tools, recovery machines and leak detectors, and installation per UL 60335-2-40 and ASHRAE 15.
- Sales: under 40 CFR 82.154, refrigerant sales are generally restricted to Section 608 (or 609 for motor-vehicle AC) certified technicians, with recordkeeping under 40 CFR 82.166. Small-can and other exceptions are in the rule.
- Pressure-temperature data comes from the refrigerant manufacturer. Blends have separate bubble and dew points.
Common mistakes
- Identifying a cylinder by color.
- Selling A1-only tools or recovery equipment for A2L work.
- Recommending "drop-in" replacements without checking oil compatibility and the manufacturer's approval.
Governing standards: ASHRAE 34 (designation and safety classification); ASHRAE 15 (safety code); UL 60335-2-40; 40 CFR 82 Subpart F; 40 CFR 84; 49 CFR 172–180 for shipping and cylinders; AHRI 700 (purity); AHRI Guideline N (container marking).
Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.