R32 vs R454B Refrigerant UK: Heat Pump & AC Comparison Guide 2025

R454B is emerging as the long-term successor to R410A in the UK AC and heat pump market, while R32 continues to dominate mid-efficiency split systems. Understanding the key differences between R32 and R454B helps HVAC engineers prepare for the shift and advise customers correctly.

R32 vs R454B: Key Specifications

Both R32 and R454B are classified as A2L refrigerants — mildly flammable — requiring specific installation safety precautions under EN 378. However, their GWP figures differ significantly:

• R32 GWP: 675 (CO2 equivalent)
• R454B GWP: 466 — 31% lower than R32
• R32 composition: Single-component HFC (difluoromethane)
• R454B composition: 68.9% R32 + 31.1% R1234yf (zeotropic blend)

R454B’s lower GWP makes it better positioned under the UK F-Gas phase-down trajectory, which targets reducing HFC consumption by 79% by 2030.

Which Brands Use R454B?

Daikin was the first major manufacturer to adopt R454B in their Altherma 3 heat pump range (marketed under the trade name R-32+ in some regions). Mitsubishi Electric and Panasonic have announced R454B models for their 2025-2026 product lines. For existing R32 systems, R454B cannot be used as a drop-in replacement — the system must be designed for R454B.

A2L Safety Requirements: R32 vs R454B

Both refrigerants share the A2L safety classification, meaning the same installation rules apply under BS EN 378-3: lower occupancy limit calculations, leak detection requirements in enclosed plant rooms, and restricted use of ignition sources during service. Engineers already certified and trained for R32 can work on R454B systems with minimal additional training — the key difference is understanding R454B’s zeotropic blending behaviour, which means it must be charged as a liquid.

Should You Stock R454B Now?

For most UK HVAC contractors in 2025, R32 remains the primary stocking refrigerant for heat pumps and split AC. R454B demand will increase significantly from 2026 as new equipment arrives. Refrigerant Gas Supplies Ltd monitors market demand and will add R454B to stock as UK availability grows. Check the full refrigerant range for current availability.