What Home Inspectors Need to Know About the Shift from R-410A to R-32 and R-454B Refrigerants
The HVAC industry is undergoing a major transition as it phases out R-410A in favor of next-generation refrigerants with lower global warming potential (GWP). Two front-runners—R-32 and R-454B—have emerged as leading replacements. For home inspectors, understanding the characteristics of these refrigerants, along with the implications for residential equipment, is critical for assessing HVAC systems during inspections in the coming years.
Historical Background: The Road to Low-GWP Alternatives
R-410A became the standard residential refrigerant in the early 2000s, replacing ozone-depleting R-22 (Freon) due to its zero ozone depletion potential (ODP). However, R-410A has a high GWP of 2,088, which places it on the list of phased-down substances under the American Innovation and Manufacturing (AIM) Act of 2020 and the international Kigali Amendment to the Montreal Protocol.
With regulatory pressure mounting, the HVAC industry has explored alternatives with much lower GWP ratings. Two primary candidates have emerged:
R-32: A pure HFC with a GWP of 675.
R-454B: A blend of HFO and HFC (68.9% R-32 and 31.1% R-1234yf) with a GWP of 466.
Phase-Out Timeline for R-410A
The Environmental Protection Agency (EPA) has mandated a step-down in high-GWP 
refrigerant use starting in 2025 for new residential and light commercial AC systems. By this time, most new systems will no longer be manufactured with R-410A, although existing systems can still be serviced with it.
2023–2024: Manufacturers began phasing in R-32 and R-454B equipment.
January 1, 2025: National restrictions on installing new R-410A equipment take effect.
2030 and beyond: Gradual reduction of R-410A service stock and replacement parts availability.
Equipment Changes Home Inspectors Should Watch For
As refrigerant types shift, the design and labeling of HVAC units have changed to reflect refrigerant properties, particularly regarding flammability and pressure levels.
Key Inspection Points:
Refrigerant Labeling: Look for factory-applied labels identifying R-32 or R-454B on compressors, condensers, and air handlers.
UL 2- and 3-L Rating Systems: Both refrigerants are classified as A2L (mildly flammable). Inspectors should look for markings and warnings related to flammability.
Pressure and Piping: R-32 operates at slightly higher pressures than R-410A, while R-454B is more similar in pressure range. New units may require modified or reinforced components.
Leak Detection Ports: Systems may feature enhanced leak detection or require low-leak brazing techniques.
Ventilation Requirements: Flammable refrigerants require additional attention to ventilation and mitigation of ignition risks in confined spaces like attics.
R-32 vs. R-454B: Which Is Superior?
Thermodynamic Performance
R-32 generally has higher cooling capacity and efficiency (especially EER and COP values) compared to R-454B.
R-454B, while slightly less efficient, has a lower GWP and better safety profile due to lower flammability risk.
Flammability & Safety
R-32: Higher flammability (A2L), with a higher heat of combustion. Requires stricter safety measures and ventilation planning.
R-454B: Also A2L, but less flammable and with a lower heat of combustion. Preferred by manufacturers prioritizing safety compliance in retrofit scenarios.
Environmental Impact
R-454B wins in GWP (466 vs. 675) and therefore is considered more environmentally friendly.
Equipment Compatibility: Interchangeable or Not?
While R-32 and R-454B are both considered low-GWP replacements for R-410A, they are not interchangeable. Each refrigerant requires specific system designs and components:
Different lubricant oils: Typically POE oils tailored to each refrigerant.
Expansion valves, coils, and compressors: Must be designed for the specific thermodynamic properties of each refrigerant.
Service tools and leak detectors: May need to be compatible with the specific refrigerant being used.
Home inspectors should not assume a unit labeled as “low-GWP” is compatible with any low-GWP refrigerant.
Cost Differences
As of 2025, cost differences exist but are subject to change:
R-32: Tends to be less expensive due to its single-component nature and large-scale production.
R-454B: More expensive per pound due to its proprietary blend and more complex manufacturing process.
However, equipment costs may offset refrigerant costs, and many OEMs are aligning with one refrigerant based on partnerships and global strategy.
What Home Inspectors Should Know Going Forward
Begin documenting refrigerant type in every HVAC system inspected post-2025.
Be aware of flammability classifications (A2L), and note any missing safety signage or labeling.
Check for updated installation practices (ventilation, leak detection, and clearance).
Educate clients on phase-out timelines, especially if they have R-410A systems nearing end-of-life.
Conclusion
The HVAC industry’s pivot toward R-32 and R-454B reflects a broader shift toward sustainability and compliance with global climate initiatives. For home inspectors, staying informed about refrigerant changes, equipment compatibility, and safety implications is no longer optional—it’s essential.
Whether it’s identifying new refrigerant types, understanding A2L safety requirements, or educating clients about future costs and system life spans, inspectors who stay ahead of the curve will provide greater value and earn more trust in the field.