Bubble vs. dew — how to read this chart
R-134a is a single-component refrigerant, so it changes state at one temperature for a given pressure — the bubble and dew points are identical and there is no glide to account for.
HVAC · PT Chart
R-134a PT Chart
Pressure–temperature saturation chart for R-134a. Convert pressure to saturation temperature and back, or print the full table.
Convert
psig
Single-component refrigerant: bubble and dew are the same.
R-134a saturation
97°F
Sat temp (dew)
97°F
Sat temp (bubble)
97°F
R-134a saturation table
psig at sea level · A1| Temp (°F) | Bubble (psig) | Dew (psig) |
|---|---|---|
| -20 | 0.3 | 0.3 |
| -18 | 0.9 | 0.9 |
| -16 | 1.5 | 1.5 |
| -14 | 2 | 2 |
| -12 | 2.6 | 2.6 |
| -10 | 3.2 | 3.2 |
| -8 | 3.8 | 3.8 |
| -6 | 4.4 | 4.4 |
| -4 | 5 | 5 |
| -2 | 5.7 | 5.7 |
| 0 | 6.5 | 6.5 |
| 2 | 7.4 | 7.4 |
| 4 | 8.3 | 8.3 |
| 6 | 9.3 | 9.3 |
| 8 | 10.4 | 10.4 |
| 10 | 11.5 | 11.5 |
| 12 | 12.7 | 12.7 |
| 14 | 14 | 14 |
| 16 | 15.3 | 15.3 |
| 18 | 16.6 | 16.6 |
| 20 | 18 | 18 |
| 22 | 19.4 | 19.4 |
| 24 | 20.9 | 20.9 |
| 26 | 22.5 | 22.5 |
| 28 | 24.1 | 24.1 |
| 30 | 25.8 | 25.8 |
| 32 | 27.6 | 27.6 |
| 34 | 29.4 | 29.4 |
| 36 | 31.2 | 31.2 |
| 38 | 33.1 | 33.1 |
| 40 | 35 | 35 |
| 42 | 37 | 37 |
| 44 | 39 | 39 |
| 46 | 41.1 | 41.1 |
| 48 | 43.3 | 43.3 |
| 50 | 45.5 | 45.5 |
| 52 | 47.8 | 47.8 |
| 54 | 50.1 | 50.1 |
| 56 | 52.5 | 52.5 |
| 58 | 55 | 55 |
| 60 | 57.5 | 57.5 |
| 62 | 60.1 | 60.1 |
| 64 | 62.7 | 62.7 |
| 66 | 65.4 | 65.4 |
| 68 | 68.2 | 68.2 |
| 70 | 71.1 | 71.1 |
| 72 | 74.1 | 74.1 |
| 74 | 77.1 | 77.1 |
| 76 | 80.2 | 80.2 |
| 78 | 83.4 | 83.4 |
| 80 | 86.7 | 86.7 |
| 82 | 90 | 90 |
| 84 | 93.5 | 93.5 |
| 86 | 97 | 97 |
| 88 | 100.6 | 100.6 |
| 90 | 104.3 | 104.3 |
| 92 | 108.1 | 108.1 |
| 94 | 112 | 112 |
| 96 | 116 | 116 |
| 98 | 120.1 | 120.1 |
| 100 | 124.3 | 124.3 |
| 102 | 128.6 | 128.6 |
| 104 | 133 | 133 |
| 106 | 137.5 | 137.5 |
| 108 | 142.1 | 142.1 |
| 110 | 146.8 | 146.8 |
| 112 | 151.6 | 151.6 |
| 114 | 156.5 | 156.5 |
| 116 | 161.5 | 161.5 |
| 118 | 166.7 | 166.7 |
| 120 | 171.9 | 171.9 |
| 122 | 177.2 | 177.2 |
| 124 | 182.7 | 182.7 |
| 126 | 188.3 | 188.3 |
| 128 | 194 | 194 |
| 130 | 199.8 | 199.8 |
| 132 | 205.8 | 205.8 |
| 134 | 211.9 | 211.9 |
| 136 | 218.1 | 218.1 |
| 138 | 224.3 | 224.3 |
| 140 | 230.5 | 230.5 |
Frequently asked
What pressure should R-134a run at?
It depends on the saturation temperature you are targeting, not a single number. Read your gauge pressure, convert it to a saturation temperature with the chart above, then compare it to your line temperature for superheat or subcooling.
Does R-134a have temperature glide?
No. R-134a is a single-component refrigerant, so the bubble and dew points are the same and there is no glide.
Is this R-134a PT chart accurate for charging?
Use it for field reference. Values come from published saturation data; still confirm against the equipment nameplate and manufacturer data for final charging.
Sources & references
- CoolProp — open-source thermophysical property library used to generate the saturation curves
- EPA Section 608 — refrigerant handling and the venting prohibition
- ASHRAE Handbook — Fundamentals — refrigerant and psychrometric property basis
Estimates for planning purposes only. Verify all results against the code edition adopted in your jurisdiction and with your Authority Having Jurisdiction (AHJ). This tool is not a substitute for a licensed HVAC contractor. See our methodology, sources, and code editions.