R454B Refrigerant UK Guide: Properties, A2L Safety and System Compatibility

R454B (Opteon XL41) is a low-GWP A2L refrigerant blend of R32 and R1234yf, with a GWP of 466 – around 78% lower than R410A. It is the leading R410A replacement for larger commercial air conditioning, heat pumps and chillers because its capacity and discharge characteristics closely match R410A while meeting the F-Gas low-GWP direction. This guide explains its properties, safety requirements and where it fits in the UK market.

What is R454B?

R454B is a near-azeotropic blend of 68.9% R32 and 31.1% R1234yf. It was developed as a close performance match to R410A, allowing manufacturers to design new equipment with similar pressures, capacity and efficiency while cutting GWP dramatically. Major OEMs including Carrier and Trane have adopted R454B across new commercial ranges.

R454B key properties

Property	Value
Composition	R32 68.9% / R1234yf 31.1%
GWP	466
ASHRAE safety class	A2L (mildly flammable)
Temperature glide	Low (~1.5K)
Capacity vs R410A	Very close match
Typical applications	Commercial AC, heat pumps, chillers, rooftop units

A2L safety – what UK engineers must know

As an A2L refrigerant, R454B is mildly flammable with a low burning velocity. Working with it requires:

• A2L-rated recovery, vacuum and charging equipment.
• Electronic leak detection suited to A2L gases.
• Charge-limit and minimum-room-area calculations following BS EN 378 and the equipment manufacturer’s instructions.
• Appropriate ventilation and ignition-source control during service.

We explain the broader A2L handling rules in our complete R32 guide, which shares the same A2L safety framework.

R454B vs R410A vs R32

	R454B	R410A	R32
GWP	466	2,088	675
Safety class	A2L	A1	A2L
Type	Blend (low glide)	Blend (near-azeotrope)	Single component
Best fit	Commercial AC / chillers	Legacy servicing	Residential / light commercial

If you are choosing between the low-GWP options for an R410A replacement project, our R32 vs R454B replacement guide walks through the decision in detail.

Handling and charging notes

Although R454B has low glide, it is still a blend and should be charged as a liquid from the cylinder and, after a significant leak, fully recovered and recharged rather than topped up to preserve composition. Always follow the system manufacturer’s charge specification.

Buying refrigerant in the UK

Refrigerant Gas Supplies Ltd supplies F-Gas compliant refrigerant to certified UK engineers. While you transition systems, we stock R32 and R410A – see the full refrigerant gas range. F-Gas certification is required to purchase.

Frequently asked questions

What is R454B made of?

R454B is a blend of 68.9% R32 and 31.1% R1234yf, giving a GWP of 466 – about 78% lower than R410A.

Is R454B a drop-in for R410A?

No. R454B is used in equipment designed and rated for A2L refrigerants. It is not a like-for-like retrofit for existing R410A systems without manufacturer approval and appropriate safety measures.

Is R454B flammable?

R454B is classified A2L – mildly flammable with low burning velocity. It requires A2L-rated tools, leak detection and charge-limit calculations under BS EN 378.

What is R454B used for?

R454B is mainly used in new commercial air conditioning, heat pumps, chillers and rooftop units as a low-GWP replacement for R410A.