commercialhvacuk
Get a Quote

Commercial HVAC refrigerants: GWP table and guide

Updated 23 October 2026 · SEO Dons Editorial

Last checked 22 October 2026. GWP figures follow the basis used in Great Britain's F-gas legislation.

Which GWP figures does Great Britain use?

The retained Regulation 517/2014 states global warming potential (GWP) values on the basis of the IPCC Fourth Assessment Report, unless it says otherwise. GOV.UK's list of F gases and common mixtures sits on the same footing, rounded to the nearest whole number. The table below uses those figures wherever they exist.

Other documents use other bases. Solstice, a refrigerant manufacturer, lists R-1234ze at a GWP of less than 1, where the GB annex lists 7. A UK propane chiller range lists R-290 at 0.02, where the GB annex gives 3. Each is right on its own terms, so ask which assessment report a quote relies on before comparing its GWP with a legal threshold.

GWP, safety class and typical use of common commercial refrigerants

The last column applies the GOV.UK method (mass in tonnes multiplied by GWP) to find the charge that reaches 5 tonnes of CO2 equivalent, where the annual leak check starts. Those kilogram figures were calculated for this page and rounded, so they are not published values. Figures for R454B, R513A and R515B come from the manufacturers' own pages, because GOV.UK's mixture list does not include them.

RefrigerantGWP (GB basis)Safety classTypical commercial useCharge reaching 5 t CO2e
R134a1,430A1Chillers; medium and high temperature refrigeration3.5 kg
R407C1,774A1Air conditioning, as an R22 replacement2.8 kg
R410A2,088A1Air-conditioning systems2.4 kg
R404A3,922A1Low and medium temperature refrigeration1.3 kg
R32675A2LAir conditioning; preferred replacement for R410A in new equipment7.4 kg
R454B466A2LAir conditioning, chillers and heat pumps10.7 kg
R513A631A1Chillers, as an R134a replacement7.9 kg
R515B293A1Chillers and high-temperature cooling17.1 kg
R1234ze7A2LAir-cooled and water-cooled chillersNot a listed HFC; see notes
R290 (propane)3A3New air conditioning and refrigeration; chillers and heat pumpsNot an F gas

Three notes on reading it:

  • Blends. R454B, R513A and R515B are mixtures, and the regulation calculates a mixture's GWP as a weighted average by weight. As a check on R515B, Solstice gives its formula as 91.1% R-1234ze and 8.9% R-227ea. With the GB figures of 7 and 3,220 that comes to about 293, the same as Solstice's published value.
  • HFOs. GOV.UK lists HFC-1234ze among the "F gases you must report on only" and says some rules do not apply to certain types of F gas, without saying which. Ask the certified contractor how the leak-check duty applies to the exact gas or mixture in a system.
  • Hydrocarbons. GOV.UK says equipment that uses hydrocarbons needs no HFC quota authorisation, and the GB annex lists propane only as a non-fluorinated substance for mixture calculations. Ammonia (R717) is listed there at 0.

One legal marker sits outside the table. Virgin F gas with a GWP above 2,500 cannot be used to top up a system holding F gas equivalent to 40 tonnes of CO2 or more, which is 10.2 kg of R404A. Reclaimed or recycled gas of that kind is allowed until 2030 only, so the rule bites on refrigeration plant far more than on comfort cooling.

How do GWP and CO2 equivalent set the leak-check duty?

The method is to multiply the mass of the gas, in metric tonnes, by its GWP. For example, take a hypothetical chiller holding 40 kg of refrigerant:

  • With R134a, 0.04 tonnes x 1,430 gives 57.2 tonnes of CO2 equivalent. That is in the 50 to under 500 tonne band, so a leak check at least every 6 months.
  • With R513A, 0.04 x 631 gives 25.2 tonnes. That is in the 5 to under 50 tonne band, so at least every 12 months.
  • With R410A, 0.04 x 2,088 gives 83.5 tonnes, which is six-monthly again.

The same physical charge can sit in a lighter band when the GWP is lower. Automatic leak detection doubles the allowed interval, and equipment at 500 tonnes or more must have it. The F-gas regulations guide covers the thresholds in full, and the page on refrigerant leaks covers what follows when one is found.

What do A1, A2L and A3 mean for charge limits?

Safety class is a separate scale from GWP. ASHRAE Standard 34 assigns safety classifications from toxicity and flammability data, and BS ISO 817 uses the same system. A1 refrigerants are non-flammable. A2L is the lower-flammability group: REFCOM describes these gases as hard to ignite, with a burning velocity of 10 cm/s or less under test conditions, though they remain rated flammable under DSEAR. A3 is highly flammable, and propane sits there.

The class matters because BS EN 378 links the permitted charge to the room. BSI says Part 1 helps identify the installation location and determine the maximum charge suitable for the room volume. CIBSE Journal works an A2L example: a floor-mounted unit holding 2.4 kg of R32 needs a room of at least 49.02 m2 with no ventilation. With a circulation fan and built-in leak detector under BS EN 60335-2-40, the same unit can go in a room of 17.4 m2. Charge, mounting height and added safeguards all move the answer.

For A3 the margin is tighter. CIBSE gives the minimum ignition energy of a typical A2L as 10 J, against about 0.0003 J for methane, and a quenching distance of 8 to 25 mm against about 1.5 mm for propane. The R290 page covers what that means for commercial equipment, and the R32 versus R454B page compares the two mainstream A2L choices.

What about R22 and other older gases?

R22 (HCFC-22) is not in the table because GOV.UK lists it as an ozone-depleting substance, not an F gas. GOV.UK's guidance says such substances must not be used in new equipment or to service existing equipment, with an exception only for recycled halons in critical uses, and that equipment containing them can still be used as long as it is not leaking. A leaking R22 system therefore cannot be topped up with R22, which is a planning point for owners of older plant.

How should the table be used on a project?

Treat it as a reference, not a recommendation. A quote for air conditioning replacement should name the refrigerant, the basis of the GWP, the charge in kilograms and the CO2 equivalent, so bids can be compared like for like. For chilled-water plant, the chiller refrigerants page compares R1234ze, R513A and the others. Readers who want quotes can send an enquiry through the site's form.

Sources

Common questions

Does a lower GWP mean a refrigerant is safer?

No. GWP measures climate effect, and safety class measures toxicity and flammability. Propane has one of the lowest GWPs in the table but sits in the most flammable class, so a low GWP can bring tighter charge and ventilation limits rather than looser ones.

Why does a datasheet show a different GWP from this table?

GB legislation states its values on the IPCC Fourth Assessment Report basis. A manufacturer may quote a figure from a later assessment, which is why R-1234ze is 7 in the GB annex and less than 1 on a manufacturer page. Ask which basis a quote uses.

How can an owner find out which refrigerant a system holds?

The equipment rating plate shows it. For systems holding F gas equivalent to 5 tonnes of CO2 or more, GOV.UK also says records of the quantity and type of gas installed and added must be kept for 5 years.

Is an HFO refrigerant such as R1234ze an F gas?

GOV.UK lists HFC-1234ze among F gases you must report on only, and says some rules do not apply to those gases. A certified contractor can confirm how the rules apply to the exact gas or mixture in a given system.

Ask for commercial HVAC quotes

SEO Dons Ltd publishes this site and replies to every enquiry by email. It does not install, service or maintain HVAC.

Get a quote
Get a quote