EPA lists R-1234yf as acceptable, subject to use conditions including SAE J639, for new passenger cars and light-duty trucks, and says it is used in the majority of light-duty vehicles. Its GWP of 4 is under the 150 limit that the AIM Act Technology Transitions rule applies to new light-duty vehicle A/C from model year 2025.
R-1234yf pressure-temperature table
Every 5°F shown. ″ Hg = inches of mercury vacuum.
R-1234yf saturation pressure, psig at sea level
°F
°C
psig
-40
-40.0
11.5″ Hg
-39
-39.4
11.1″ Hg
-38
-38.9
10.5″ Hg
-37
-38.3
10.0″ Hg
-36
-37.8
9.5″ Hg
-35
-37.2
8.9″ Hg
-34
-36.7
8.4″ Hg
-33
-36.1
7.8″ Hg
-32
-35.6
7.2″ Hg
-31
-35.0
6.6″ Hg
-30
-34.4
6.0″ Hg
-29
-33.9
5.4″ Hg
-28
-33.3
4.8″ Hg
-27
-32.8
4.1″ Hg
-26
-32.2
3.5″ Hg
-25
-31.7
2.8″ Hg
-24
-31.1
2.1″ Hg
-23
-30.6
1.4″ Hg
-22
-30.0
0.7″ Hg
-21
-29.4
0.0
-20
-28.9
0.4
-19
-28.3
0.7
-18
-27.8
1.1
-17
-27.2
1.5
-16
-26.7
1.9
-15
-26.1
2.3
-14
-25.6
2.7
-13
-25.0
3.1
-12
-24.4
3.5
-11
-23.9
4.0
-10
-23.3
4.4
-9
-22.8
4.8
-8
-22.2
5.3
-7
-21.7
5.8
-6
-21.1
6.2
-5
-20.6
6.7
-4
-20.0
7.2
-3
-19.4
7.7
-2
-18.9
8.2
-1
-18.3
8.7
0
-17.8
9.2
1
-17.2
9.7
2
-16.7
10.3
3
-16.1
10.8
4
-15.6
11.4
5
-15.0
11.9
6
-14.4
12.5
7
-13.9
13.1
8
-13.3
13.7
9
-12.8
14.3
10
-12.2
14.9
11
-11.7
15.5
12
-11.1
16.2
13
-10.6
16.8
14
-10.0
17.5
15
-9.4
18.1
16
-8.9
18.8
17
-8.3
19.5
18
-7.8
20.2
19
-7.2
20.9
20
-6.7
21.6
21
-6.1
22.3
22
-5.6
23.1
23
-5.0
23.8
24
-4.4
24.6
25
-3.9
25.4
26
-3.3
26.2
27
-2.8
26.9
28
-2.2
27.8
29
-1.7
28.6
30
-1.1
29.4
31
-0.6
30.3
32
0.0
31.1
33
0.6
32.0
34
1.1
32.9
35
1.7
33.8
36
2.2
34.7
37
2.8
35.6
38
3.3
36.5
39
3.9
37.5
40
4.4
38.4
41
5.0
39.4
42
5.6
40.4
43
6.1
41.4
44
6.7
42.4
45
7.2
43.4
46
7.8
44.5
47
8.3
45.5
48
8.9
46.6
49
9.4
47.7
50
10.0
48.8
51
10.6
49.9
52
11.1
51.0
53
11.7
52.2
54
12.2
53.3
55
12.8
54.5
56
13.3
55.7
57
13.9
56.9
58
14.4
58.1
59
15.0
59.3
60
15.6
60.6
61
16.1
61.8
62
16.7
63.1
63
17.2
64.4
64
17.8
65.7
65
18.3
67.1
66
18.9
68.4
67
19.4
69.8
68
20.0
71.1
69
20.6
72.5
70
21.1
74.0
71
21.7
75.4
72
22.2
76.8
73
22.8
78.3
74
23.3
79.8
75
23.9
81.3
76
24.4
82.8
77
25.0
84.3
78
25.6
85.9
79
26.1
87.4
80
26.7
89.0
81
27.2
90.6
82
27.8
92.3
83
28.3
93.9
84
28.9
95.6
85
29.4
97.3
86
30.0
99.0
87
30.6
100.7
88
31.1
102.4
89
31.7
104.2
90
32.2
106.0
91
32.8
107.8
92
33.3
109.6
93
33.9
111.4
94
34.4
113.3
95
35.0
115.2
96
35.6
117.1
97
36.1
119.0
98
36.7
120.9
99
37.2
122.9
100
37.8
124.9
101
38.3
126.9
102
38.9
128.9
103
39.4
130.9
104
40.0
133.0
105
40.6
135.1
106
41.1
137.2
107
41.7
139.4
108
42.2
141.5
109
42.8
143.7
110
43.3
145.9
111
43.9
148.1
112
44.4
150.4
113
45.0
152.7
114
45.6
155.0
115
46.1
157.3
116
46.7
159.6
117
47.2
162.0
118
47.8
164.4
119
48.3
166.8
120
48.9
169.2
121
49.4
171.7
122
50.0
174.2
123
50.6
176.7
124
51.1
179.3
125
51.7
181.8
126
52.2
184.4
127
52.8
187.0
128
53.3
189.7
129
53.9
192.3
130
54.4
195.0
131
55.0
197.7
132
55.6
200.5
133
56.1
203.3
134
56.7
206.1
135
57.2
208.9
136
57.8
211.7
137
58.3
214.6
138
58.9
217.5
139
59.4
220.5
140
60.0
223.4
141
60.6
226.4
142
61.1
229.4
143
61.7
232.5
144
62.2
235.6
145
62.8
238.7
146
63.3
241.8
147
63.9
245.0
148
64.4
248.2
149
65.0
251.4
150
65.6
254.7
151
66.1
257.9
152
66.7
261.3
153
67.2
264.6
154
67.8
268.0
155
68.3
271.4
156
68.9
274.9
157
69.4
278.3
158
70.0
281.8
159
70.6
285.4
160
71.1
288.9
Saturation pressures computed with CoolProp 8.0.0 (R1234yf) on October 10, 2026, gauge pressure at sea level. Checked against National Refrigerants published chart at 8 points; largest difference 0.13 psi. How these numbers are made.
What R-1234yf is and where it is used
R-1234yf (HFO-1234yf, 2,3,3,3-tetrafluoropropene) is a single-component hydrofluoroolefin. Chemours sells it as Opteon YF. Solstice Advanced Materials, created in 2025 from the former Advanced Materials business of Honeywell, sells it as Solstice yf and calls it a near drop-in replacement for R-134a in car A/C. EPA says automakers began moving to it in light-duty vehicles in 2012 and that it is now used in the majority of them. Chemours also offers it as Opteon XL10 for new stationary refrigeration and AC equipment that would have used R-134a.
Its 100-year GWP is 4 (AR4), against 1430 for R-134a. It is ASHRAE safety group A2L: in Chemours' summary of the ASHRAE 34 scheme, "A" means lower toxicity and "2L" means mildly flammable. Chemours says Opteon YF may require additional safety measures during implementation, use and service compared with R-134a because of its A2L classification. See what A2L refrigerants change for techs.
How to read the R-1234yf chart
R-1234yf is a single compound, so the chart has one pressure per temperature and the same column serves superheat and subcooling. It boils at -21.0°F at atmospheric pressure, so the coldest rows read in vacuum: at -30°F the chart shows 6.0 in Hg vacuum.
Superheat: a suction reading of 33 psig converts to 34.1°F. Subtract that from the suction line temperature.
Subcooling: a liquid line reading of 150 psig converts to 111.8°F. Subtract the liquid line temperature from it.
The figures below are worked examples at assumed coil temperatures, not specifications for any vehicle:
Low side: an evaporator at 35°F reads about 33.8 psig, against 30.4 psig for R-134a.
High side: at 110°F and 120°F condensing temperatures, R-1234yf reads 145.9 psig and 169.2 psig. R-134a would read 146.4 psig and 171.2 psig.
R-1234yf reads a little higher than R-134a at evaporator temperatures and a little lower at hot condensing temperatures, and Chemours describes its performance and operating characteristics as similar to R-134a. That similarity is not a reason to mix them. The vehicle's service information governs. R-134a vs R-1234yf compares the two in detail.
Service notes
Not a retrofit refrigerant: Chemours states that Opteon YF cannot be used for retrofit applications. Do not charge it into an R-134a system.
Vehicle requirements: EPA's use conditions require new vehicle systems to meet the safety requirements of SAE J639, including a flammable refrigerant warning label, a high-pressure compressor cutoff switch, pressure relief devices and unique fittings. Manufacturers must also keep a failure mode and effects analysis under SAE J1739 on file for at least three years.
Tools: Chemours says Opteon YF requires recovery or RRR equipment meeting SAE J2843 or J2851, leak detectors meeting J2913, and refrigerant identifiers meeting J2927 or J2912, or the VDA equivalents.
Oil: National Refrigerants says automotive systems use PAG oil, while POE can be used in refrigeration applications. Chemours lists Opteon YF as compatible with POE lubricants and with PAGs formulated specifically for R-1234yf.
Charging: as a single compound it does not fractionate. Use equipment and procedures specified for R-1234yf by the vehicle or equipment maker.