R-32 PT Chart

About R-32

R-32 is a single-component HFC and half of the R-410A blend. Used on its own, it has about a third of R-410A’s GWP, which puts it under the 700 GWP limit for new US residential AC and heat pumps.

R-32 is classed A2L, mildly flammable. As a single component it has no glide, so the chart has one pressure column. Its pressures run slightly above R-410A, and its discharge temperatures run noticeably hotter.

• New residential split AC and heat pumps, including Daikin and its Goodman and Amana brands
• Ductless mini-splits, widely used in Asia and Europe for years
• Component of R-410A, R-454B, R-407C and R-448A

R-32 Properties

Key facts for identifying R-32 and choosing tools, oil and replacements.

• R-410A PT chart

Typical R-32 Operating Pressures

Suction pressure is the vapor (dew) pressure at the evaporator temperature; head pressure is the liquid (bubble) pressure at the condensing temperature. The temperatures are common design points, not charging targets.

• Check R-32 superheat and subcooling

How to Read the R-32 PT Chart

The chart covers -38°F to 150°F. Pressures are gauge pressure (psig), the number your manifold shows; switch to °C and kPa above if you work in metric.

The chart has one pressure column because liquid and vapor share the same saturation pressure at each temperature. Use the same column for superheat (suction side) and subcooling (liquid side).

To read it, find the pressure on your gauge and read across to the saturation temperature, or start from a temperature and read the pressure. The lookup above interpolates between rows for you.

Superheat and Subcooling Formulas

The PT chart turns a gauge pressure into a saturation temperature. Compare that with a line temperature to get superheat or subcooling.

Tsuction

Suction line temperature near the outdoor unit or compressor, °F

Tliquid

Liquid line temperature leaving the condenser, °F

Tsat

Saturation temperature at the gauge pressure, °F

Gauge pressure (psig) is pressure above atmospheric. Below 0 psig, the chart shows vacuum in inches of mercury.

Worked Example: R-32 Superheat and Subcooling

AC cooling, 95°F outdoor: an R-32 system reads 121.0 psig suction with a 50°F suction line, and 401.4 psig on the liquid line with a 105°F liquid line.

1. Saturation temperature at 121.0 psig: 40.0°F.
2. Superheat: 50°F − 40.0°F = 10.0°F.
3. Saturation temperature at 401.4 psig: 115.0°F.
4. Subcooling: 115.0°F − 105°F = 10.0°F.

Result: 10.0°F superheat and 10.0°F subcooling. Compare them with the manufacturer’s targets before adding or recovering refrigerant.

Is R-32 Being Phased Out?

R-32 is one of the two main replacements for R-410A in new US residential equipment, alongside R-454B. With a GWP of 675, it meets the 700 limit that took effect for new systems in 2025.

Because it is an A2L refrigerant, R-32 equipment carries extra safety requirements: leak detection and mitigation controls in some systems, A2L-rated recovery machines and vacuum pumps, and storage rules for cylinders.

R-32 Field Tips

Practical points for working on R-32 systems, from the sources below.

1. 1

   Expect a smaller charge

   R-32 systems hold less refrigerant than an R-410A system of the same size. Charge by the nameplate weight and the manufacturer’s subcooling target; habits from R-410A lead to overcharging.

2. 2

   Watch discharge temperature

   R-32 discharge temperatures run well above R-410A at the same conditions. A high reading is not automatically a fault, but compare it with the manufacturer’s limit before you call the compressor bad.

3. 3

   Use A2L-rated equipment

   Recovery machines, vacuum pumps and leak detectors that touch the refrigerant need to be rated for A2L refrigerants. Ventilate the work area and keep ignition sources away from open lines.

Sources: IIR: Study of R-32 for residential air conditioning, Ferguson: A2L refrigerant tool compatibility, Chadwell Supply: A2L refrigerant tools and storage