RefrigerantASHRAE R-438A

R438A (MO99) PT Chart

Q: Why does R-438A contain hydrocarbons?

To improve oil return to the compressor. The hydrocarbons are 2.3% of the blend by mass: 1.7% R-600 and 0.6% R-601a. The blend is classified A1.

Updated October 12, 2026

R-438A · MO99

A1 Lower toxicity, no flame propagationHFC blend Contains AIM Act HFCs

Illustration of a refrigerant cylinder painted light green gray (RAL 7044), the color AHRI Guideline N-2017 calls for on all new refrigerant containers from 2020^{[3], section 4.8}. Label: R-438A, safety class A1, GWP 2,265. No red band: AHRI Guideline N-2017 reserves it for flammable refrigerants^{[3], section 4.7}.

R-32/R-125/R-134a/R-600/R-601a (8.5/45/44.2/1.7/0.6)

Blend of three HFCs and two hydrocarbons: 8.5% R-32, 45% R-125, 44.2% R-134a, 1.7% R-600 and 0.6% R-601a by mass^[5]. Safety class A1^[1]; GWP 2,265 under 40 CFR 84.64(b)^[6]. Chemours' retrofit guidelines present it as a replacement for R-22 in direct-expansion air conditioning and in medium- and low-temperature refrigeration, usually without an oil change^[7].

Transcribed row for row from Appendix B of the Chemours Freon™ MO99 Retrofit Guidelines (C-10862, August 2016)^{[7], Appendix B}; all 103 rows were checked against the document. Not yet compared with an independent source.

Saturation @ 70°F

130.9 / 112.3 PSIG

GWP (100-yr)

2,265 computed under 40 CFR 84.64(b) from component values

Temperature glide

9.5°F

Boiling point

bubble −44.2°F / dew −33.0°F

Sourced facts

ASHRAE safety class: A1^[1]
Composition (mass): 8.5% R-32 / 45% R-125 / 44.2% R-134a / 1.7% R-600 / 0.6% R-601a^[5]
GWP (100-yr): 2,265^{[6], §84.64(b), computed}
ODP: 0^[9]
Normal boiling point: bubble −44.2°F (−42.3°C), dew −33.0°F (−36.1°C)^{[7], Appendix B, 0 psig row}
Lubricant: Mineral oil, alkylbenzene or POE^[7]
Trade name: Freon™ MO99^[7]

R-438A PT calculator Superheat

Lower toxicity, no flame propagation

Lower toxicity (Occupational Exposure Limit ≥ 400 ppm). No flame propagation in air at standard atmospheric pressure and 60°C. R-134a, R-22, R-410A, R-404A, R-744 (CO2) are A1.

Flammability: None (no flame propagation)
Toxicity: Lower (OEL ≥ 400 ppm)

Classification per ANSI/ASHRAE Standard 34-2022^{[1], safety group definitions and refrigerant safety classifications}. See full reference.

Saturation pressure-temperature — datasheet table

Chemours Freon™ MO99 Refrigerant (R-438A) Retrofit Guidelines, Publication C-10862 (August 2016), Appendix B^{[7], Appendix B}

Pressure (psig)	Bubble °F (saturated liquid)	Dew °F (saturated vapor)	Glide °F
−6.0	−63.0	−51.5	11.5
−5.0	−59.3	−47.8	11.5
−4.0	−55.8	−44.5	11.3
−3.0	−52.6	−41.3	11.3
−2.0	−49.6	−38.4	11.2
−1.0	−46.8	−35.6	11.2
0.0	−44.2	−33.0	11.2
1.0	−41.7	−30.6	11.1
2.0	−39.3	−28.2	11.1
3.0	−37.0	−26.0	11.0
4.0	−34.8	−23.9	10.9
5.0	−32.7	−21.8	10.9
6.0	−30.7	−19.8	10.9
7.0	−28.8	−18.0	10.8
8.0	−26.9	−16.1	10.8
9.0	−25.1	−14.4	10.7
10.0	−23.4	−12.6	10.8
12.0	−20.1	−9.4	10.7
14.0	−16.9	−6.3	10.6
16.0	−13.9	−3.4	10.5
18.0	−11.1	−0.6	10.5
20.0	−8.4	2.0	10.4
22.0	−5.8	4.6	10.4
24.0	−3.4	7.0	10.4
26.0	−1.0	9.3	10.3
28.0	1.3	11.6	10.3
30.0	3.5	13.7	10.2
32.0	5.7	15.8	10.1
34.0	7.7	17.8	10.1
36.0	9.7	19.8	10.1
38.0	11.7	21.7	10.0
40.0	13.6	23.5	9.9
42.0	15.4	25.3	9.9
44.0	17.2	27.1	9.9
46.0	18.9	28.8	9.9
48.0	20.6	30.4	9.8
50.0	22.3	32.1	9.8
52.0	23.9	33.7	9.8
54.0	25.5	35.2	9.7
56.0	27.0	36.7	9.7
58.0	28.6	38.2	9.6
60.0	30.1	39.6	9.5
62.0	31.5	41.1	9.6
64.0	32.9	42.5	9.6
66.0	34.3	43.8	9.5
68.0	35.7	45.2	9.5
70.0	37.1	46.5	9.4
75.0	40.3	49.7	9.4
80.0	43.5	52.7	9.2
85.0	46.5	55.7	9.2
90.0	49.4	58.5	9.1
95.0	52.2	61.2	9.0
100.0	54.9	63.9	9.0
105.0	57.5	66.4	8.9
110.0	60.1	68.9	8.8
115.0	62.6	71.3	8.7
120.0	65.0	73.6	8.6
125.0	67.3	75.9	8.6
130.0	69.6	78.1	8.5
135.0	71.8	80.3	8.5
140.0	73.9	82.4	8.5
145.0	76.0	84.4	8.4
150.0	78.1	86.4	8.3
155.0	80.1	88.4	8.3
160.0	82.1	90.3	8.2
165.0	84.0	92.1	8.1
170.0	85.9	94.0	8.1
175.0	87.8	95.8	8.0
180.0	89.6	97.5	7.9
185.0	91.4	99.2	7.8
190.0	93.1	100.9	7.8
195.0	94.8	102.6	7.8
200.0	96.5	104.2	7.7
205.0	98.2	105.8	7.6
210.0	99.8	107.4	7.6
215.0	101.4	108.9	7.5
220.0	103.0	110.5	7.5
225.0	104.6	112.0	7.4
230.0	106.1	113.4	7.3
235.0	107.6	114.9	7.3
240.0	109.1	116.3	7.2
245.0	110.5	117.7	7.2
250.0	112.0	119.1	7.1
255.0	113.4	120.5	7.1
260.0	114.8	121.8	7.0
265.0	116.2	123.1	6.9
270.0	117.6	124.4	6.8
275.0	118.9	125.7	6.8
280.0	120.3	127.0	6.7
285.0	121.6	128.3	6.7
290.0	122.9	129.5	6.6
295.0	124.2	130.7	6.5
300.0	125.4	131.9	6.5
310.0	127.9	134.3	6.4
320.0	130.4	136.6	6.2
330.0	132.7	138.9	6.2
340.0	135.1	141.1	6.0
350.0	137.4	143.3	5.9
360.0	139.6	145.4	5.8
370.0	141.8	147.5	5.7
380.0	143.9	149.5	5.6
390.0	146.1	151.5	5.4
400.0	148.1	153.4	5.3

R-438A — 103 rows, −6 to 400 psig. Bubble = saturated liquid (use for subcooling); dew = saturated vapor (use for superheat on zeotropic blends).

At a glance

Chemistry

R-32/R-125/R-134a/R-600/R-601a (8.5/45/44.2/1.7/0.6)

Quinary HFC blend with hydrocarbons

Lubricant compatibility

MOABPOE

Its two hydrocarbons are there to improve oil return to the compressor^[7]. Sold by Chemours as Freon™ MO99 for R-22 retrofits; in most systems no oil change is needed, and the existing mineral oil or alkylbenzene can stay^[7]. The guidelines recommend adding POE (about 20% of the oil charge) in some systems, such as those with liquid receivers, and POE oil for screw compressors and for Trane 3-D and Danfoss SM scroll compressors^[7].

Blend composition

R-32 8.5%
R-125 45.0%
R-134a 44.2%
R-600 1.7%
R-601a 0.6%

Trade names

Freon™ MO99 — Chemours^[7]

Common applications

R-22 retrofit: direct-expansion residential and commercial AC, and medium- and low-temperature refrigeration^[7]
Works with the existing mineral oil or alkylbenzene in most systems^[7]

Properties

Boiling point (1 atm)
−44.2°F (−42.3°C)
Critical point
No single point — blend critical locus
Molar mass
99.10 g/mol
Temperature glide
11.2°F
ODP
0
GWP (100-yr)
2,265 computed under 40 CFR 84.64(b) from component values IPCC: AR4 not assessed · AR5 not assessed · AR6 not assessed
New-equipment status (US)
Restricted in 48 new-equipment categories — US new-equipment rules (40 CFR 84.54).

What is R-438A?

R-438A is a quinary HFC blend with two small hydrocarbon components: R-32 (8.5%) + R-125 (45%) + R-134a (44.2%) + R-600 (1.7%) + R-601a (0.6%) by mass^[1].^{[1], refrigerant designations}

Chemours sells R-438A as Freon™ MO99^[7].

Where R-438A is used

R-22 retrofits in direct-expansion residential and commercial air conditioning^[7]
R-22 retrofits in medium- and low-temperature refrigeration^[7]

Regulatory & phase-down status

R-438A contains HFC-32, HFC-125 and HFC-134a, regulated substances under the AIM Act^{[8], 42 U.S.C. 7675(c)(1)}, and 40 CFR 84.54 restricts it in new equipment in the categories listed on this page^[2]. Under SNAP, EPA lists it as acceptable in new and retrofitted supermarket systems^[9] and as unacceptable in new cold storage warehouses from January 1, 2023^[10].

Service notes

Mineral oil, alkylbenzene, or POE all compatible.^[7] Its glide is about 9.5°F at a 40°F dew point (interpolated between the 60 and 62 psig rows of Appendix B)^{[7], Appendix B}; the guidelines use the dew temperature for superheat and the bubble temperature for subcooling^[7]. A1 classification means no A2L procedures required.

Phase-down timeline

R-438A contains HFC-32, HFC-125 and HFC-134a, regulated substances under the AIM Act^{[8], 42 U.S.C. 7675(c)(1)}. Its GWP under 40 CFR 84.64 is 2,265, at or above the limit in 48 of the categories 40 CFR 84.54 restricts (listed under “All 84.54 categories restricting R-438A”).

From January 1, 2025 — new self-contained residential & light-commercial AC and heat pump products: manufacture / import restricted (GWP ≥ 700)^{[2], §84.54(a)(1)}.
From January 1, 2025 — new retail food refrigeration — stand-alone units: manufacture / import restricted (GWP ≥ 150)^{[2], §84.54(a)(4)}.
From January 1, 2025 — new refrigerated transport — road and marine (self-contained products): manufacture / import restricted (listed refrigerant)^{[2], §84.54(a)(7)}.
From January 1, 2025 — new residential & light-commercial AC and heat pump systems (except VRF): installation restricted (GWP ≥ 700), unless every specified component was manufactured or imported before January 1, 2025^{[2], §84.54(c)(1)}.
From January 1, 2025 — new refrigerated transport — road or marine systems: installation restricted (listed refrigerant)^{[2], §84.54(c)(8)}.
From January 1, 2026 — new ice makers — batch type up to 1,000 lb of ice per 24 h and continuous type up to 1,200 lb per 24 h: manufacture / import restricted (GWP ≥ 150)^{[2], §84.54(a)(8)(i)}.
From January 1, 2026 — new variable refrigerant flow (VRF) residential & light-commercial AC and heat pump systems: installation restricted (GWP ≥ 700); systems whose specified components were all manufactured or imported before January 1, 2026 may be installed until January 1, 2027, or until January 1, 2028 when a building permit issued before October 5, 2023 specifies the refrigerant^{[2], §84.54(c)(2)}.
From July 27, 2026 — new refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higher: manufacture / import restricted (GWP ≥ 700)^{[2], §84.54(a)(6)}.
From July 27, 2026 — new retail food refrigeration — remote condensing units: installation restricted (GWP ≥ 1,400)^{[2], §84.54(c)(11)(i)}.
From July 27, 2026 — new refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higher: installation restricted (GWP ≥ 700)^{[2], §84.54(c)(7)}.
From July 27, 2026 — new cold storage warehouse systems: installation restricted (GWP ≥ 700)^{[2], §84.54(c)(9)(i)}.
From January 1, 2027 — new ice makers — batch type above 1,000 lb of ice per 24 h and continuous type above 1,200 lb per 24 h: manufacture / import restricted (listed refrigerant)^{[2], §84.54(a)(8)(ii)}.
From January 1, 2027 — new supermarket systems: installation restricted (GWP ≥ 1,400)^{[2], §84.54(c)(12)(i)}.
From January 1, 2027 — new automatic commercial ice machines with a remote condenser: installation restricted (listed refrigerant)^{[2], §84.54(c)(14)}.
From January 1, 2028 — new retail food refrigeration — stand-alone units: sale and distribution restricted (GWP ≥ 150)^{[2], §84.54(b)}.
From January 1, 2032 — new retail food refrigeration — remote condensing units: installation restricted at GWP ≥ 150 for systems with 200 lb or more of refrigerant (except the high-temperature side of a cascade system), and at GWP ≥ 300 for systems under 200 lb and for the high-temperature side of a cascade system^{[2], §84.54(c)(11)(ii)}.
From January 1, 2032 — new supermarket systems: installation restricted at GWP ≥ 150 for systems with 200 lb or more of refrigerant (except the high-temperature side of a cascade system), and at GWP ≥ 300 for systems under 200 lb and for the high-temperature side of a cascade system^{[2], §84.54(c)(12)(ii)}.
From January 1, 2032 — new cold storage warehouse systems: installation restricted at GWP ≥ 150 for systems with 200 lb or more of refrigerant (except the high-temperature side of a cascade system), and at GWP ≥ 300 for systems under 200 lb and for the high-temperature side of a cascade system^{[2], §84.54(c)(9)(ii)}.

HFC production & consumption allowances step down to 30% of baseline in 2029–2033, 20% of baseline in 2034–2035, and 15% of baseline in 2036 and later (42 U.S.C. 7675(e)(2)(C))^[8].

Full 40 CFR 84.54 new-equipment rules for R-438A →

US new-equipment rules (40 CFR 84.54)

R-438A contains HFC-32, HFC-125 and HFC-134a, regulated substances under the AIM Act^{[8], 42 U.S.C. 7675(c)(1)}. Under 40 CFR 84.64(b) its GWP is 2,265: each component's GWP times its mass fraction; components without a GWP under 84.64 are left out (84.64(c)). That value is compared against each 40 CFR 84.54 subsector limit below.

Effective	Equipment subsector	Limit	Restriction	¶
January 1, 2025	Self-contained residential & light-commercial AC and heat pump products	GWP ≥ 700	Manufacture / import	(a)(1)
January 1, 2025	Retail food refrigeration — stand-alone units	GWP ≥ 150	Manufacture / import	(a)(4)
January 1, 2025	Refrigerated transport — road and marine (self-contained products)	listed refrigerant	Manufacture / import	(a)(7)
January 1, 2025	Residential & light-commercial AC and heat pump systems (except VRF)	GWP ≥ 700	Installation	(c)(1)
January 1, 2025	Refrigerated transport — road or marine systems	listed refrigerant	Installation	(c)(8)
January 1, 2026	Ice makers — batch type up to 1,000 lb of ice per 24 h and continuous type up to 1,200 lb per 24 h	GWP ≥ 150	Manufacture / import	(a)(8)(i)
January 1, 2026	Variable refrigerant flow (VRF) residential & light-commercial AC and heat pump systems	GWP ≥ 700	Installation	(c)(2)
July 27, 2026	Refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higher	GWP ≥ 700	Manufacture / import	(a)(6)
July 27, 2026	Retail food refrigeration — remote condensing units	GWP ≥ 1,400	Installation	(c)(11)(i)
July 27, 2026	Refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higher	GWP ≥ 700	Installation	(c)(7)
July 27, 2026	Cold storage warehouse systems	GWP ≥ 700	Installation	(c)(9)(i)
January 1, 2027	Ice makers — batch type above 1,000 lb of ice per 24 h and continuous type above 1,200 lb per 24 h	listed refrigerant	Manufacture / import	(a)(8)(ii)
January 1, 2027	Supermarket systems	GWP ≥ 1,400	Installation	(c)(12)(i)
January 1, 2027	Automatic commercial ice machines with a remote condenser	listed refrigerant	Installation	(c)(14)
January 1, 2028	Retail food refrigeration — stand-alone units	GWP ≥ 150	Sale / distribution	(b)
January 1, 2028	Refrigerated transport — road and marine (self-contained products)	listed refrigerant	Sale / distribution	(b)
January 1, 2028	Self-contained residential & light-commercial AC and heat pump products	GWP ≥ 700	Sale / distribution	(b)
January 1, 2029	Ice makers — batch type up to 1,000 lb of ice per 24 h and continuous type up to 1,200 lb per 24 h	GWP ≥ 150	Sale / distribution	(b)
July 27, 2029	Refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higher	GWP ≥ 700	Sale / distribution	(b)
January 1, 2030	Ice makers — batch type above 1,000 lb of ice per 24 h and continuous type above 1,200 lb per 24 h	listed refrigerant	Sale / distribution	(b)
January 1, 2032	Retail food refrigeration — remote condensing units	GWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)	Installation	(c)(11)(ii)
January 1, 2032	Supermarket systems	GWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)	Installation	(c)(12)(ii)
January 1, 2032	Cold storage warehouse systems	GWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)	Installation	(c)(9)(ii)

All 84.54 categories restricting R-438A (48)^[2]

Refrigeration, air conditioning & heat pumps (41)
January 1, 2025	Self-contained residential & light-commercial AC and heat pump products	GWP ≥ 700	(a)(1)
January 1, 2025	Chillers for comfort cooling	GWP ≥ 700	(a)(10)(i)
January 1, 2025	Chillers for ice rinks	GWP ≥ 700	(a)(10)(ii)
January 1, 2025	Residential dehumidifiers	GWP ≥ 700	(a)(2)
January 1, 2025	Household refrigerators and freezers	GWP ≥ 150	(a)(3)
January 1, 2025	Retail food refrigeration — stand-alone units	GWP ≥ 150	(a)(4)
January 1, 2025	Vending machines	GWP ≥ 150	(a)(5)
January 1, 2025	Refrigerated transport — road and marine (self-contained products)	listed refrigerant	(a)(7)
January 1, 2025	Residential & light-commercial AC and heat pump systems (except VRF)	GWP ≥ 700	(c)(1)
January 1, 2025	Chillers for comfort cooling	GWP ≥ 700	(c)(3)
January 1, 2025	Ice rinks	GWP ≥ 700	(c)(4)
January 1, 2025	Refrigerated transport — road or marine systems	listed refrigerant	(c)(8)
January 1, 2026	Chillers for industrial process refrigeration, fluid exiting the chiller warmer than −22°F (−30°C)	GWP ≥ 700	(a)(10)(iii)
January 1, 2026	Industrial process refrigeration products (non-chiller), charge 200 lb or greater, refrigerant entering the evaporator warmer than −22°F (−30°C)	GWP ≥ 150	(a)(12)(i)
January 1, 2026	Industrial process refrigeration products (non-chiller), charge less than 200 lb, refrigerant entering the evaporator warmer than −22°F (−30°C)	GWP ≥ 300	(a)(12)(ii)
January 1, 2026	Ice makers — batch type up to 1,000 lb of ice per 24 h and continuous type up to 1,200 lb per 24 h	GWP ≥ 150	(a)(8)(i)
January 1, 2026	Industrial process refrigeration systems (non-chiller), charge 200 lb or greater, evaporator inlet warmer than −22°F (−30°C), not the high-temperature side of a cascade	GWP ≥ 150	(c)(10)(i)
January 1, 2026	Industrial process refrigeration systems (non-chiller), charge less than 200 lb, evaporator inlet warmer than −22°F (−30°C)	GWP ≥ 300	(c)(10)(ii)
January 1, 2026	Industrial process refrigeration — high-temperature side of cascade systems, evaporator inlet warmer than −22°F (−30°C)	GWP ≥ 300	(c)(10)(iii)
January 1, 2026	Variable refrigerant flow (VRF) residential & light-commercial AC and heat pump systems	GWP ≥ 700	(c)(2)
January 1, 2026	Chillers for industrial process refrigeration, fluid exiting the chiller warmer than −22°F (−30°C)	GWP ≥ 700	(c)(5)(i)
July 27, 2026	Refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higher	GWP ≥ 700	(a)(6)
July 27, 2026	Retail food refrigeration — remote condensing units	GWP ≥ 1,400	(c)(11)(i)
July 27, 2026	Refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higher	GWP ≥ 700	(c)(7)
July 27, 2026	Cold storage warehouse systems	GWP ≥ 700	(c)(9)(i)
January 1, 2027	Self-contained products in data center, information technology equipment facility, and computer room cooling	GWP ≥ 700	(a)(11)
January 1, 2027	Ice makers — batch type above 1,000 lb of ice per 24 h and continuous type above 1,200 lb per 24 h	listed refrigerant	(a)(8)(ii)
January 1, 2027	Refrigerated food processing and dispensing products outside the scope of UL 621, charge 500 g or less	GWP ≥ 150	(a)(9)(i)
January 1, 2027	Refrigerated food processing and dispensing products outside the scope of UL 621, charge greater than 500 g	listed refrigerant	(a)(9)(ii)
January 1, 2027	Supermarket systems	GWP ≥ 1,400	(c)(12)(i)
January 1, 2027	Data center, information technology equipment facility, and computer room cooling systems	GWP ≥ 700	(c)(13)
January 1, 2027	Automatic commercial ice machines with a remote condenser	listed refrigerant	(c)(14)
January 1, 2027	Refrigerated food processing and dispensing equipment with a remote condenser	listed refrigerant	(c)(15)
January 1, 2028	Chillers for industrial process refrigeration, fluid exiting the chiller from −58°F to −22°F (−50°C to −30°C)	GWP ≥ 700	(a)(10)(iv)
January 1, 2028	Industrial process refrigeration products (non-chiller), refrigerant entering the evaporator from −58°F to −22°F (−50°C to −30°C)	GWP ≥ 700	(a)(12)(iii)
January 1, 2028	Refrigerated food processing and dispensing products within the scope of UL 621 (ice cream makers)	listed refrigerant	(a)(9)(iii)
January 1, 2028	Industrial process refrigeration systems (non-chiller), evaporator inlet from −58°F to −22°F (−50°C to −30°C)	GWP ≥ 700	(c)(10)(iv)
January 1, 2028	Chillers for industrial process refrigeration, fluid exiting the chiller from −58°F to −22°F (−50°C to −30°C)	GWP ≥ 700	(c)(6)(i)
January 1, 2032	Retail food refrigeration — remote condensing units	GWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)	(c)(11)(ii)
January 1, 2032	Supermarket systems	GWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)	(c)(12)(ii)
January 1, 2032	Cold storage warehouse systems	GWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)	(c)(9)(ii)
Motor vehicle air conditioning (3)
October 24, 2024	Motor vehicle air-conditioning in Model Year 2025 and later light-duty passenger cars and trucks (gross vehicle weight rating under 8,500 lb)	GWP ≥ 150	(a)(13)(i)
Model Year 2028	Motor vehicle air-conditioning in medium-duty passenger vehicles, heavy-duty pickup trucks and complete heavy-duty vans whose air-conditioning will not be modified by upfitters	GWP ≥ 150	(a)(13)(ii)
January 1, 2028	Motor vehicle air-conditioning in certain nonroad vehicles (agricultural tractors over 40 horsepower; self-propelled agricultural machinery; compact equipment; construction, forestry and mining equipment; and commercial utility vehicles)	GWP ≥ 150	(a)(13)(iii)
Foam blowing agents (2)
January 1, 2025	Foam products: rigid polyurethane appliance foam, commercial refrigeration foam, laminated boardstock, marine flotation foam, sandwich panels, slabstock; flexible polyurethane; integral skin polyurethane; polystyrene (extruded boardstock, billet, extruded sheet); phenolic insulation board and bunstock; polyisocyanurate laminated boardstock; polyolefin; rigid polyurethane spray foam	GWP ≥ 150	(a)(14)
January 1, 2026	Foam products in the (a)(14) formulations for use in space and military applications	GWP ≥ 150	(a)(15)
Aerosol propellants / solvents (2)
January 1, 2025	Aerosol products	GWP ≥ 150	(a)(16)(i)
January 1, 2028	Aerosol products (all, except defense sprays as defined in 84.3)	GWP ≥ 150	(a)(16)(ii)

Servicing. 40 CFR 84.54 restricts new manufacture/import, later sale/distribution, and installation. "Installation" is defined in 84.54(e); repairing or servicing existing R-438A equipment is not an installation unless it meets 84.54(e), so existing systems can keep being serviced. From January 1, 2029, servicing or repairing R-438A equipment in supermarket systems, refrigerated transport or automatic commercial ice makers must be done with reclaimed refrigerant^[4].

EU (retail-food / cold-storage)

Under Regulation (EU) No 517/2014, since replaced by (EU) 2024/573, applying from March 11, 2024 (compared against the AR4 headline GWP), R-438A's GWP is at or above the limit in:

Annex III row 11: Refrigerators and freezers for commercial use (hermetically sealed equipment) — GWP ≥ 150, from January 1, 2022.
Annex III row 13: Multipack centralised refrigeration systems for commercial use with a rated capacity of 40 kW or more — GWP ≥ 150, from January 1, 2022 (the primary refrigerant circuit of a cascade system may use GWP below 1,500).

Regulation (EU) No 517/2014.

Source: 40 CFR 84.54, current through 91 FR 31329 (May 26, 2026). Installation defined at 40 CFR 84.54(e).

Global warming potential, in context

R-22 retrofit blends

Retrofit and replacement paths

R-438A replaces

R-22 A1 · GWP 1,810

Replacements for R-438A

Reading the R-438A PT chart

R-438A is a zeotropic blend (ASHRAE 400 series)^[5]; the table gives bubble and dew temperatures, about 9.5°F apart at a 40°F dew point^{[7], Appendix B}. Use dew curve at suction pressure for superheat; bubble curve at discharge for subcooling.^{[7], dew for superheat, bubble for subcooling}

Frequently asked

›What is R-438A used for?

Retrofitting R-22 systems — direct-expansion air conditioning and medium- and low-temperature refrigeration — usually without an oil change. The guidelines exclude centrifugal compressors and chillers with flooded evaporators^[7].

R-438A has 45% R-125 and 8.5% R-32; R-422D has 65.1% R-125 and no R-32^[5].

›What's R-438A's GWP?

2,265 under 40 CFR 84.64(b), against 2,729 for R-422D, also computed under 84.64(b)^[6]; R-22's GWP is 1,810 (IPCC AR4)^{[11], Table 2.14}. 40 CFR 84.54 restricts it in new equipment in the categories listed on this page^[2]; servicing existing systems is not an installation under 84.54(e)^{[2], §84.54(e)}.

›What's the difference between R-438A and R-422D?

R-438A has five components, including 8.5% R-32; R-422D has three (R-125, R-134a and R-600a) and no R-32^[5]. R-438A's GWP is lower: 2,265 against 2,729, both under 40 CFR 84.64(b)^[6].

›Why does R-438A contain hydrocarbons?

To improve oil return to the compressor^[7]. The hydrocarbons are 2.3% of the blend by mass: 1.7% R-600 and 0.6% R-601a^[5].

The blend is classified A1^[1].

›Is R-438A safe to handle?

ASHRAE safety group A1: lower toxicity and no flame propagation^[1].

Download this dataset

Full PT table for R-438A · from Appendix B of the Freon™ MO99 Retrofit Guidelines (C-10862) · attribute the source

CSV JSON

Sources & citations

[1]
ANSI/ASHRAE Standard 34-2022, Designation and Safety Classification of Refrigerants (free read-only version). ASHRAE. 2022. https://www.ashrae.org/technical-resources/standards-and-guidelines/read-only-versions-of-ashrae-standards (accessed October 2, 2026)
[2]
40 CFR 84.54 — Restrictions on the use of hydrofluorocarbons. eCFR (Office of the Federal Register). up to date as of 9/29/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-B/section-84.54 (accessed October 2, 2026)
[3]
2017 Guideline for Assignment of Refrigerant Container Colors (AHRI Guideline N-2017). AHRI. 2017. https://www.ahrinet.org/system/files/2023-06/AHRI_Guideline_N_2017.pdf (accessed October 2, 2026)
[4]
40 CFR 84.112 — Reclamation. eCFR (Office of the Federal Register). up to date as of 9/25/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-C/section-84.112 (accessed October 2, 2026). 89 FR 82859, Oct. 11, 2024
[5]
ASHRAE Refrigerant Designations. ASHRAE. web page, updated May 25, 2021. https://www.ashrae.org/technical-resources/standards-and-guidelines/ashrae-refrigerant-designations (accessed October 2, 2026)
[6]
40 CFR 84.64 — Global warming potentials. eCFR (Office of the Federal Register). current as of 9/28/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-B/section-84.64 (accessed October 2, 2026)
[7]
Freon™ MO99 Refrigerant (R-438A) Retrofit Guidelines. Chemours. C-10862 (8/16). https://www.freon.com/en/-/media/files/freon/freon-mo99-retrofit-guidelines.pdf?rev=acdad5438acc4f4487fa72b7a4a3cae3&hash=DED9DFB65CBF946BF9D0CF8B1477E896 (accessed October 5, 2026)
[8]
42 U.S.C. 7675 — American Innovation and Manufacturing Act. US Code (via Cornell LII). current. https://www.law.cornell.edu/uscode/text/42/7675 (accessed October 2, 2026)
[9]
Substitutes in Typical Supermarket Systems. US EPA (SNAP). last updated March 20, 2026. https://www.epa.gov/snap/substitutes-typical-supermarket-systems (accessed October 5, 2026)
[10]
Substitutes in Cold Storage Warehouses. US EPA (SNAP). last updated March 19, 2026. https://www.epa.gov/snap/substitutes-cold-storage-warehouses (accessed October 5, 2026)
[11]
IPCC AR4 WG1 (2007), Chapter 2, Table 2.14, 100-year Global Warming Potentials. IPCC AR4 Working Group I. 2007. https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter2-1.pdf (accessed October 2, 2026)