# R-438A — HVAC refrigerant replacements: retrofit compatibility, safety class, GWP and lubricant

For R-438A, replaces is R-22; trade name(s) is Freon™ MO99™; ashrae safety class is A1; gwp is 2264 (2059); compatible lubricant is MO, AB, POE, verified against its source on 2026-08-11.

- **Refrigerant:** R-438A _(verified: appears in the quote below)_
- **Replaces:** R-22 _(verified: appears in the quote below)_
- **Trade name(s):** Freon™ MO99™ _(verified: appears in the quote below)_
- **ASHRAE safety class:** A1 _(verified: appears in the quote below)_
- **GWP:** 2264 (2059) _(verified: appears in the quote below)_
- **Compatible lubricant:** MO, AB, POE _(verified: appears in the quote below)_

## What the source says

> Freon™ MO99™ R-438A A1 2264 (2059) MO, AB, POE elastomeric seals require replacement. R-22 Replacements for Great choice in systems where changing to POE oil is not practical,

## What epa.gov says

> R-22 Retrofit Blends R-404A R-407A R-407C R-407F R-417A R-417B R-421A R-421B R-422A R-422B R-422C R-422D R-424A R-427A R-428A R-434A R-438A R-507A

Source: https://www.epa.gov/sites/default/files/documents/Choosing_Right_R22_Retrofit.pdf

## Sources disagree

More than one authority states this, and they do not state the same
thing. Both are reproduced with the source each came from.

### Trade name(s)

chemours.com says trade name(s) is **Freon™ MO99™**, as of 2026-08-11.

> Freon™ MO99™ R-438A A1 2264 (2059) MO, AB, POE elastomeric seals require replacement. R-22 Replacements for Great choice in systems where changing to POE oil is not practical,

Source: https://www.chemours.com/en/-/media/files/freon/opteon-freon-general-replacement-guide.pdf

freon.com says trade name(s) is **Freon™ MO99**, as of 2026-08-11.

> Freon™ MO99 (R-438A) is the best overall all performance when using R-407C? match (energy efficiency, capacity, operating pressures, and If R-407C is used without a full oil change to POE, there is mass flow rates) to R-22 in air conditioning applications.

Source: https://www.freon.com/en/-/media/files/freon/freon-mo99-faq.pdf


## Source

- https://www.chemours.com/en/-/media/files/freon/opteon-freon-general-replacement-guide.pdf
- https://www.freon.com/en/-/media/files/freon/freon-mo99-faq.pdf
- https://www.epa.gov/sites/default/files/documents/Choosing_Right_R22_Retrofit.pdf

Last verified: 2026-08-11. Review by: 2027-08-11.
Part of [HVAC refrigerant replacements: retrofit compatibility, safety class, GWP and lubricant](https://referencesource.org/hvac-component-refrigerant-compatibility/).