R32 refrigerant explained for London homeowners

What a refrigerant does

Every air conditioner and heat pump has a fluid circulating through its pipes called a refrigerant. It boils at a low temperature, so it can absorb heat from the room as it evaporates in the indoor coil, then give that heat out as it condenses in the outdoor coil after the compressor squeezes it. In heating mode the flow reverses. The refrigerant is not used up, it just goes round, which is why a sealed home system should never need routine topping up.

What R32 is

R32 is a single component refrigerant called difluoromethane. Over the last decade it has become the standard in new domestic split systems from most major manufacturers, replacing R410A, which was itself a blend that included R32.

	R410A	R32
Type	blend of two refrigerants	single refrigerant
Global warming potential	much higher	much lower, around a third of R410A
Safety class	A1, non flammable	A2L, mildly flammable
Typical use today	older systems, some commercial	most new home splits and air to air heat pumps
Charge needed	more	less for the same output

Global warming potential, or GWP, compares how strongly a gas traps heat in the atmosphere against carbon dioxide over a set period. The lower figure is the main reason R32 replaced R410A in new home equipment.

Why it matters under the F-gas rules

Both R410A and R32 are fluorinated gases, or F gases, so the same legal rules apply. Anyone installing, servicing or repairing the refrigerant side must hold a personal F-gas qualification, and the company must be certified by an approved body. Gov.uk lists Refcom, the F-Gas Register (Quidos) and Bureau Veritas for air conditioning and heat pumps.

The leak checking rules are based on the climate impact of the refrigerant in the system, expressed as tonnes of CO2 equivalent. Equipment at or above 5 tonnes of CO2 equivalent needs regular leak checks (gov.uk). Because R32 has a lower GWP, a home system needs a larger charge before it reaches that line, and most single room home systems sit well below it.

Is mildly flammable a worry?

The A2L class means R32 can burn under certain conditions, but it is hard to ignite and burns slowly compared with flammable gases such as LPG. Manufacturers set limits on how much refrigerant can be used for the size of the room an indoor unit serves, and installers follow those limits and the installation manual. The system is sealed and pressure tested before it is charged, so in normal use the refrigerant stays inside the pipes.

What this means for you:

• use an F-gas qualified engineer from a certified company, never a DIY kit
• do not drill near the pipe route without knowing where it runs
• if you smell anything unusual and cooling is weak, switch off, ventilate the room and book a check

What it means for older systems

Plenty of London homes and offices still run R410A systems fitted ten or more years ago. They can carry on if they are working well and serviced. The questions come when something fails:

• small leak or minor fault: repair with the same refrigerant is often fine
• major leak in a coil, or a failed compressor on an old unit: replacement may be the better long term choice
• repeated refrigerant top ups: a sign the leak has never been found and fixed

You cannot simply switch an R410A system to R32 by changing the gas. The units are designed for one refrigerant. If you replace an old system, it is sometimes possible to reuse existing pipework after cleaning and testing, depending on the manufacturer’s rules and the pipe condition. The old refrigerant must be recovered properly, not vented. Our guide to home air conditioning regassing explains why leaks matter.

Efficiency

R32 works efficiently in smaller domestic systems, which is part of why manufacturers adopted it. When comparing new units, look at the SEER for cooling and SCOP for heating on the product label, rather than the refrigerant name alone. A well sized R32 split, installed with tidy pipework and commissioned to the correct charge, will get closer to its rated efficiency than a poorly installed one.

A local example

In an Ealing 1930s semi with an R410A split fitted years ago in the back bedroom, the owners notice weaker cooling each summer. A diagnosis finds a slow leak at a flare joint. The engineer repairs the joint, pressure tests, evacuates and recharges with R410A. The system is fine for now. If the same house later wants a multi split for three bedrooms, a new R32 system would be the natural choice. Our Ealing area page covers local planning, and our split system page explains how new systems are installed.