R-32 vs R-454B vs R-410A: What’s the Difference?

Air conditioners and heat pumps are in the middle of a refrigerant transition. If you have an older system with R-410A or you are planning a new install, you will see model lines with R-32 or R-454B. What changed, why it matters, and which path fits your home or facility? This guide explains the differences in performance, safety, regulations, and service so you can make informed decisions.

Why refrigerants are changing in the U.S.

Two forces are driving the change. First, modern HVAC aims to deliver high efficiency with lower environmental impact. Second, federal and state rules are phasing down high‑GWP HFCs. Under the U.S. AIM Act, the national supply of HFCs is being reduced 85% by 2036. California’s CARB rule requires most new residential and light commercial comfort cooling equipment sold from 2025 to use refrigerants below a 750 GWP threshold. R-410A, with a GWP around 2088, does not meet those limits for new equipment. Low‑GWP A2L refrigerants like R-32 and R-454B do.

R-32 vs R-454B vs R-410A at a glance

• Environmental impact (GWP): R-410A ≈ 2088; R-32 ≈ 675; R-454B ≈ 466. All have zero ozone depletion potential.
• Safety class (ASHRAE 34): R-410A is A1 (non‑flammable). R-32 and R-454B are A2L (mildly flammable) with low flame speed and higher ignition energy than common fuels. They require specific installation practices.
• Operating pressure: R-32 typically runs somewhat higher pressures than R-410A; R-454B is similar to or slightly lower than R-410A. Component ratings and controls are refrigerant‑specific.
• Efficiency and capacity: Well‑designed R-32 systems can deliver notable efficiency gains vs R-410A. R-454B systems are designed to match or modestly exceed R-410A performance, often improving SEER2 and HSPF2. Real‑world results depend on coil design, compressor tech, and charge optimization.
• Charge size and layout: A2L systems may have charge limits tied to room volume and equipment location. Modern units are engineered to comply when installed per code.
• Noise and comfort: Differences come more from equipment design than from refrigerant choice itself. Look at whole‑system specs, not just the refrigerant label.

Safety and codes for A2L refrigerants

A2L systems are safe when installed and serviced to current standards. The key reference is UL 60335-2-40 (4th edition), adopted in modern model codes (IMC/UMC 2024) and rolling into jurisdictions. Requirements can include airflow verification, refrigerant detection in some applications, electrical protection, and clear labeling. Many Authorities Having Jurisdiction (AHJs) in Los Angeles County, Orange County, Ventura County, and Western Riverside County are updating permit processes accordingly.

Handling any refrigerant is not a DIY task. EPA Section 608 certification is required for service, and insurers often require licensed, qualified professionals for installations or repairs. Improper work can create safety hazards and jeopardize code compliance, warranties, and insurance coverage.

Can you retrofit an R-410A system to R-32 or R-454B?

There is no approved “drop‑in” replacement. Even though R-32 and R-454B may seem close to R-410A, the differences in flammability class, pressures, oil management, expansion devices, sensors, and controls mean the entire system is engineered and listed for a specific refrigerant. Retrofitting would typically violate manufacturer listings and local codes, and it can void warranties and create liability issues with insurers. The practical path is:

• Keep servicing an existing R-410A system until end of life, using the correct refrigerant and procedures.
• When replacing, select a system designed and listed for R-32 or R-454B that meets current codes and performance targets.

Installation and commissioning details that matter

• Design: Perform a right‑sized load calculation, match indoor/outdoor coils, verify line set size and maximum lengths/elevation, and ensure required airflow.
• Safety: Follow UL 60335-2-40 and local IMC/UMC requirements. In certain spaces, leak detection and specific ventilation or airflow provisions are mandatory.
• Piping and tightness: Use rated materials, perform strength and nitrogen pressure tests, and ensure proper brazing practices with nitrogen purge.
• Evacuation and charging: Deep evacuation (e.g., to 500 microns), weighed‑in charge per the nameplate, and refrigerant‑specific tools approved for A2L where applicable.
• Controls and documentation: Update labels, post refrigerant and charge data, and document start‑up readings for future maintenance and insurance records.

Availability, servicing, and cost

R-410A will remain available for servicing existing systems for years, but overall HFC supply is tightening under the AIM Act. That can create price swings. New A2L systems require technician training and, in some cases, updated recovery machines, hoses, and manifold gauges rated for A2L. Expect manufacturers to optimize R-32 and R-454B product lines with improved coil designs and variable‑speed compressors to raise SEER2 while maintaining reliability.

What this means for Southern California homes and facilities

Hot summers in inland parts of Los Angeles County and Western Riverside County push cooling loads, while coastal Orange County and Ventura County see milder mixed conditions and salty air. System choice should consider efficiency at part load, corrosion resistance, filtration for wildfire smoke events, and code adoption timing by your city or county. Cities we commonly see adopting updated rules include Los Angeles, Long Beach, Santa Monica, Pasadena, Glendale, Burbank, Anaheim, Irvine, Santa Ana, Fullerton, Oxnard, Thousand Oaks, Ventura, Riverside, Corona, and Temecula.

About #1 AC Guys

#1 AC Guys is a family‑owned HVAC company rooted in Los Angeles and serving Los Angeles County and nearby areas, including Orange County, Ventura County, and Western Riverside County. Our family of engineers is now in its 4th generation, with 80+ years of experience in engineering. Our engineers have trained at manufacturer facilities of Fujitsu (Japan), Mitsubishi Electric (Thailand), Midea (China), Gree (China), and Haier (China). We specialize in commercial and residential work, especially large and complex projects. Our mission is healthy air at home for healthy living.

Key takeaways

• R-32 and R-454B cut GWP dramatically vs R-410A while supporting high efficiency.
• A2L refrigerants are safe when installed and serviced to current UL 60335-2-40 and IMC/UMC requirements.
• There is no drop‑in retrofit from R-410A to R-32 or R-454B; proper replacement is the compliant route.
• Regulatory changes like the AIM Act and CARB 2025 rules are accelerating adoption, so plan accordingly.