Awaiting expert review. This page covers safety or regulatory rules that change over time. It is kept out of search results until a qualified reviewer has checked it; the sources below are dated so you can verify each point.
Quick answer
R-32, or difluoromethane (HFC-32), is a single-compound hydrofluorocarbon refrigerant with a GWP of 675 on EPA's table, used in many new air conditioners, heat pumps and mini-splits as a lower-GWP alternative to R-410A.
It is classed A2L, mildly flammable, so equipment using it follows UL 60335-2-40 charge, labeling and leak-detection rules. It is also the main ingredient in R-454B.
Quick facts
The key facts about R-32 Refrigerant, with sources:
- Chemical
- Difluoromethane (CH₂F₂), a single compound
- GWP (EPA reference table)
- 675 (IPCC AR4) 2
- Safety class
- A2L (mildly flammable) 3
- Glide
- None (single compound)
- Saturation at 40°F / 110°F
- 135.65 / 389.58 psia (about 121 / 375 psig) 1
- EPA SNAP
- Acceptable subject to use conditions in new residential and light commercial AC/HP; listed in Rules 19, 23 and 25 4
- New-system GWP limit
- Under 700 from 1 January 2025: R-32 qualifies 6
Key takeaways
- R-32 is a single compound, so it has no glide and its pressure-temperature data is simple 1.
- Its EPA GWP of 675 is under the 700 limit for new residential systems 2 6.
- It is A2L: equipment has charge limits by room size, warning labels and often a leak sensor 3.
- It is not a retrofit for R-410A systems; SNAP listings cover new equipment designed for it 4.
- Only certified technicians trained for flammable refrigerants should service it 7 3.
What R-32 is
R-32 is difluoromethane, a small HFC molecule. It has been used for years as half of R-410A and as most of R-454B. Some makers now use it on its own.
On its own, its GWP is 675 on EPA's Technology Transitions table, compared with 2,088 for R-410A 2. That puts it under the 700 limit EPA set for new residential and light commercial AC and heat pump systems from 1 January 2025 6.
It is an A2L refrigerant, mildly flammable. A current Goodman R-32 manual lists mandatory A2L instructions, requires personnel certified to work on flammable refrigerants, and describes a refrigerant detection system built into the unit 3.
How an R-32 unit responds to a leak (one maker's design)
- Refrigerant sensor detects R-32 above 25% of its lower flammability limit 3
- → unit enters mitigation: compressor and heating or cooling stop
- → indoor blower keeps running to dilute the leaked refrigerant
- → once levels fall, the unit stays in mitigation 5 more minutes
- → normal operation resumes; a technician should find and fix the leak
How R-32 behaves in a system
R-32 runs the usual refrigeration cycle. Because it is one compound, it boils and condenses at a single temperature for each pressure, with no glide. NIST data give its saturation pressure as 135.65 psia at 40°F, a typical cooling evaporator temperature, and 389.58 psia at 110°F, a typical hot-day condensing temperature 1.
That makes charging checks straightforward: a technician reads the pressure, looks up the temperature for R-32, and works out superheat or subcooling. Gauges must be set to R-32; using an R-410A or R-454B chart gives the wrong temperature.
Sources: [1]
R-32 pressure-temperature data (NIST)
| Saturation temperature | Pressure (psia) | Approx. gauge (psig) | Typical role |
|---|---|---|---|
| 30°F | 113.79 | 99 | Below-freezing coil |
| 40°F | 135.65 | 121 | Cooling evaporator |
| 50°F | 160.54 | 146 | Light-load evaporator |
| 95°F | 317.61 | 303 | Mild-day condenser |
| 110°F | 389.58 | 375 | Hot-day condenser |
| 120°F | 444.04 | 429 | Very hot day or dirty coil |
Worked example: R-32 vs R-410A vs R-454B on a 10 lb charge
GWPs from EPA's reference table 2. The 10-pound charge is assumed for illustration; CO₂e = charge × GWP.
| Refrigerant | GWP | CO₂e if the whole charge leaked | vs R-410A |
|---|---|---|---|
| R-410A | 2,088 | 20,880 lb (about 9.5 metric tons) | — |
| R-32 | 675 | 6,750 lb (about 3.1 metric tons) | About 68% lower |
| R-454B | 465 | 4,650 lb (about 2.1 metric tons) | About 78% lower |
R-32 cuts the climate effect of a leak by about two-thirds compared with R-410A. R-454B cuts it further, by blending R-32 with a near-zero-GWP HFO. Both are A2L and both are for new equipment only.
How leaks are found on R-32 systems
Leak searching on a flammable refrigerant has its own rules. The Goodman R-32 manual says potential ignition sources must never be used to search for leaks, and a halide torch or any detector with a naked flame must not be used 3.
Electronic detectors are allowed, but the manual warns their sensitivity may not be adequate for flammable refrigerants or may need recalibration, done in a refrigerant-free area.
The detector must not itself be an ignition source, must suit the refrigerant, and must be set at a percentage of the lower flammability limit, 25% at most 3.
Bubble fluids also work, but detergents containing chlorine should be avoided because chlorine can react with the refrigerant and corrode copper piping. If a leak is suspected, all naked flames must be removed or put out 3.
Sources: [3]
Where you see R-32
Pros and cons of R-32
What it does well
Limits and cautions
R-32 equipment is designed around its flammability class. The Goodman manual says auxiliary devices that could be ignition sources, such as hot surfaces above 700°C and electric switching devices, must not be installed in the ductwork, and accessories such as electronic air cleaners must be powered through the maker's accessory board 3.
Room size matters. The indoor unit lists a minimum room area; at higher altitude the installer multiplies it by an adjustment factor 3. Putting the unit in a smaller space than designed breaks the safety basis.
Sources: [3]
Cost drivers
What moves the cost of an R-32 system: equipment type and efficiency, the refrigerant detection system and accessory board if required, a matched indoor coil, line sets, and installer training for A2L work. Service visits may take longer because of A2L procedures.
HyreHVAC does not print prices without enough local quotes. See the cost calculator and our refrigerant transition research.
Installing and servicing R-32 (pro checklist)
- Confirm minimum room area from the serial plate, adjusted for altitude 3.
- Keep ignition sources out of ductwork; connect accessories through the approved board 3.
- Leak-test without flames; a halide torch must not be used 3.
- Evacuate below 500 microns and hold for 10 minutes; under 1,000 microns and steady means leak-free 3.
- Charge with R-32 to the maker's target.
- Keep the leak detection system powered except for service 3.
Owner care
Safety and warning signs
- Unexpected compressor stop with the blower running may be a leak mitigation event 3: ventilate and call a technician.
- If a leak is suspected, remove or put out any open flames 3.
- Do not use candles, lighters or torches near a suspected leak.
- Liquid refrigerant causes freeze burns.
- Use only technicians certified for flammable refrigerants 3.
Rules for R-32 (checked 10 October 2026)
AIM Act limit. With a GWP of 675, R-32 meets the 700 limit in 40 CFR 84.54 for new residential and light commercial AC and heat pump systems effective 1 January 2025 6.
SNAP safety listings. EPA states that HFC-32 is among refrigerants listed as acceptable, subject to use conditions, in new residential and light commercial AC and heat pumps under SNAP Rules 19 (2015), 23 (2021) and 25 (2023).
Its November 2025 Rule 27 proposal would update those conditions to UL 60335-2-40 4th edition or require NRTL certification; as of the April 2026 fact sheet it remained a proposal 4.
The codified SNAP appendix also lists HFC-32 for self-contained room air conditioners made from 10 May 2015 to before 30 May 2023 under UL 484 conditions 5.
Handling. Section 608 certification is required for service 7.
R-32 vs related refrigerants
| R-32 | R-454B | R-410A | |
|---|---|---|---|
| GWP (EPA) | 675 | 465 | 2,088 |
| Makeup | Single compound | 68.9% R-32 + 31.1% R-1234yf | HFC blend |
| Glide | None | About 1.5 K | Not covered here |
| Class | A2L | A2L | Not A2L |
Common misconceptions
- Myth R-32 is too flammable for homes.
- Reality It is A2L, mildly flammable; equipment meets UL 60335-2-40 limits and labels 4.
- Myth R-32 can top up an R-410A system.
- Reality Mixing refrigerants is not allowed; R-32 is for equipment designed for it.
- Myth R-32 has the lowest GWP option.
- Reality R-454B is lower on EPA's table, 465 vs 675 2.
Local codes and altitude
Federal rules set refrigerant limits; local codes govern A2L installation details, and adoption varies.
Altitude also matters: one R-32 manual requires installers to raise the minimum room area with an altitude factor, and limits operation to 8,000 feet above sea level 3.
That is a real consideration in mountain areas of states such as Arizona and California.
When this matters to you
If you are choosing between new systems, R-32 and R-454B are both compliant choices; pick on equipment quality, efficiency and the installer's A2L experience. If you own an R-32 unit, keep its sensor powered and use a trained technician.
Next step: compare best mini-splits, where R-32 is common.
Questions about R-32 Refrigerant
What is R-32 refrigerant?
R-32 is difluoromethane, a single-compound HFC refrigerant. EPA's table lists its GWP at 675. It is used in many new air conditioners, heat pumps and mini-splits and is classed A2L, mildly flammable.
Is R-32 allowed in the US?
Yes. Its GWP is under the 700 limit for new residential and light commercial systems, and EPA lists it as acceptable subject to use conditions in new residential and light commercial AC and heat pumps.
Is R-32 safe?
It is mildly flammable, so equipment follows UL 60335-2-40 rules on charge size, labels and often leak sensors. In one maker's design, a sensor stops the compressor and runs the blower if R-32 rises above 25% of its flammability limit.
What is the difference between R-32 and R-410A?
R-32 is a single compound with a GWP of 675 and is A2L. R-410A is an HFC blend with a GWP of 2,088 and is not A2L. They are not interchangeable in the same equipment.
What is the pressure of R-32?
It depends on temperature. NIST data list 135.65 psia, about 121 psig, at 40°F and 389.58 psia, about 375 psig, at 110°F. Technicians use R-32-specific data to convert pressure to temperature.
Can R-32 be used to recharge an R-410A system?
No. Refrigerants must not be mixed, and A2L refrigerants are listed for new equipment designed for them. An R-410A system must be serviced with R-410A.
Why might a mini-split use R-32?
It is a single compound with a lower GWP than R-410A, which keeps charging simple. Mini-splits also hold relatively small charges, which helps when A2L rules limit charge by room size. Check the data plate to see what your unit uses.
Who can service an R-32 system?
An EPA Section 608 certified technician who is also trained for flammable refrigerants. The Goodman R-32 manual requires personnel certified to work on units with flammable refrigerants.
Sources
- NIST Chemistry WebBook, Thermophysical Properties of Fluid Systems: difluoromethane (R-32) saturation properties, 30°F–120°F, retrieved .
- U.S. EPA, Technology Transitions GWP Reference Table (updated 2 April 2026), retrieved .
- Goodman / ACiQ, A/GPHM3 13.4 SEER2 M-Series packaged heat pump with R-32, installation instructions (IOG-3035B, 2025), retrieved .
- U.S. EPA, Fact Sheet: Proposed SNAP Rule 27 (April 2026), retrieved .
- eCFR, 40 CFR Part 82 Subpart G, Appendix R: SNAP substitutes subject to use restrictions (2011, 2015 and 2023 rules), retrieved .
- eCFR, 40 CFR Part 84 Subpart B, §§ 84.52–84.56 (version of 1 September 2026), retrieved .
- U.S. EPA, Section 608 Technician Certification, retrieved .
- Chemours, Opteon XL41 (R-454B) Product Information (C-11001, 9/2016), retrieved .
Expert review
Written by the HyreHVAC Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Held under G-REV. Saturation data from NIST; GWPs from EPA's reference table; SNAP status from EPA's Rule 27 fact sheet and the eCFR text of 40 CFR 82 Subpart G Appendix R.
AIM Act limit from 40 CFR 84.54; A2L design and service requirements from the Goodman R-32 manual; all read 10 October 2026.
The 10 lb charge in the example is assumed.
Suggest a correction. We fix errors and say what changed.