Fluorinated gases and fugitive emissions: how to calculate scope 1 refrigerant leaks

Refrigerant leaks are usually the scope 1 line item that catches people off guard in a first greenhouse gas inventory: there is no fuel invoice behind it, but every kilogram of fluorinated gas that escapes from a cooling or air-conditioning unit carries a global warming potential (GWP) far above CO2, and a single leak in a plant room can throw off the entire scope 1 footprint of a services or distribution business. You calculate it either by mass balance on refills or with a leak-rate factor by equipment type, and in the EU, Regulation (EU) 2024/573 on fluorinated gases adds mandatory periodic leak checks and a per-equipment record you want ready before an auditor asks for it.

Why this line item slips under the radar

The scope 1 footprint of a company with offices, stores or small plants usually gets reduced, in the mind of whoever is building the inventory, to fleet fuel and little else. The refrigerants in air-conditioning units, cold rooms, process chillers or server room cooling stay off the radar because they do not generate a recurring invoice: the gas is bought once, at installation, and only reappears when a leak forces a refill. The catch is that even a small refill in kilograms can represent tonnes of CO2 equivalent if the refrigerant has a high global warming potential, as many HFCs still in use do.

The other reason this figure is surprising is that a leak is, by definition, never measured directly: it is inferred. That is why the calculation method you choose largely determines the quality of the result.

Two GHG Protocol methods for calculating fugitive emissions

The GHG Protocol offers two approaches for quantifying fugitive refrigerant emissions, set out in its calculation tools for the refrigeration and air-conditioning sector.

Mass balance with refills

This is the most precise method when the data exists. It rests on a simple principle: all the gas that has to be added to a closed system to bring it back to its nominal charge is gas that leaked since the last refill or since commissioning. Simplified, the formula is:

• Emissions for the period = initial charge of the equipment + refills during the period − final measured charge − gas recovered at decommissioning.

The result in kilograms is multiplied by the specific refrigerant's GWP to get tonnes of CO2 equivalent. This method requires an exact record of every service visit, with the weight of gas added or removed each time, which in practice only works if the maintenance contractor documents it systematically.

Leak-rate factor by equipment type

When there is no reliable refill history, or this is the first inventory a company has ever built, an estimated annual leak-rate factor by equipment type is used instead (for example, a percentage of the total installed charge assumed lost each year for fixed commercial refrigeration versus lower-risk hermetic systems). It is faster but also more conservative and less precise, and you should document which sector source the applied factor comes from, since there is no single accepted value for every equipment type or sector.

Situation	Recommended method	Why
Maintenance records show kilograms per refill	Mass balance	Traceable back to the contractor's invoice and more defensible to an auditor
First inventory, no refill history	Leak-rate factor by equipment type	Lets you estimate without delaying the inventory, while you improve the underlying data
Hermetic, low-charge equipment with no interventions	Low leak-rate factor or documented exemption	Regulation (EU) 2024/573 itself exempts this equipment below a threshold from checks

Whichever method you use, document the criterion chosen per site and keep it consistent year over year: switching from mass balance to a leak-rate factor without explanation is one of the inconsistencies that draws the most questions in a carbon footprint audit. The result in tonnes of CO2 equivalent is added to the rest of the organization's carbon footprint sources within scope 1.

What Regulation (EU) 2024/573 on fluorinated gases requires

Regulation (EU) 2024/573 of 7 February 2024 on fluorinated greenhouse gases replaced the earlier Regulation (EU) No 517/2014 and widened both the scope of regulated gases (hydrofluorocarbons, perfluorocarbons, sulphur hexafluoride, nitrogen trifluoride and hydrofluoroolefins) and the control obligations for anyone operating refrigeration, air-conditioning, heat pump, electrical switchgear, fire-protection, foam, technical aerosol and solvent equipment.

Periodic leak checks by CO2-equivalent threshold

The obligation to periodically check for leaks kicks in from 5 tonnes of CO2 equivalent of charge in the equipment (or 1 kilogram for certain Annex II gases outside foams), calculated with the global warming potential values the regulation itself sets. Frequency depends on the charge:

Equipment charge (CO2e)	Frequency without a detector	Frequency with an automatic leak detection system
Between 5 and 50 tonnes	At least every 12 months	At least every 24 months
Between 50 and 500 tonnes	At least every 6 months	At least every 12 months
500 tonnes or more	At least every 3 months	At least every 6 months

Hermetically sealed equipment that is correctly labelled as such is exempt from these checks if its charge is below 10 tonnes of CO2 equivalent (or 2 kilograms for Annex II gases), and the threshold drops to 3 kilograms for equipment installed in residential buildings. Electrical switchgear with a manufacturer-certified leak rate below 0.1% a year can also be exempt if labelled accordingly.

When a check finds a leak, the regulation requires it to be repaired without undue delay, with the repair verified within one month.

Equipment records: what to keep and for how long

For every piece of equipment subject to checks, you must keep a record with at least: the quantity and type of fluorinated gas installed, the quantities added at each service visit with date and reason, whether the gas used is virgin, recycled or reclaimed, quantities recovered, interventions carried out by certified personnel, the outcome of each leak check, and the measures taken when decommissioning the equipment. The regulation requires these records to be kept for at least five years, and they are exactly the documents that back up both the mass balance described above and any auditor's review.

The regulation also sets out a progressive schedule of market-placement restrictions for new equipment with high-GWP gases, phased in by equipment type and capacity between 2025 and 2035, within the broader HFC quota phase-down running to 2050. Before planning an equipment replacement, check the current schedule for your specific equipment category directly in the regulation's text or with your supplier, because the dates vary considerably by installation type.

What to ask your refrigeration contractor for

Most of the data for this line item does not come from the sustainability team: it sits with the refrigeration and air-conditioning maintenance company. For every piece of equipment and every visit, ask for:

• The service report with the date, refrigerant type and kilograms added or removed.
• The leak-check result where applicable, and whether any detected leak was repaired.
• The equipment's nominal charge sheet and commissioning date, so you can reconstruct the mass balance if a year is missing.
• Confirmation of whether the refill gas is virgin, recycled or reclaimed, since it can affect the applicable factor in some schemes.

If the contractor only issues an invoice without a kilogram breakdown, ask for that breakdown from your very first contract: it is the document that underpins this whole line item, and the first thing an auditor will ask for.

Global warming potential of the most common refrigerants

For Annex I HFCs, Regulation (EU) 2024/573 keeps the global warming potential values from the IPCC's Fourth Assessment Report (AR4), in line with the Montreal Protocol, while for Annex II hydrofluoroolefins it uses more recent Sixth Assessment Report (AR6) values where available. That creates a real gap with sustainability reporting frameworks (GHG Protocol, ESRS E1, SBTi), which typically work with AR5 or AR6 values: the same leak, expressed in tonnes of CO2 equivalent, can produce a different figure depending on whether you use the regulatory GWP or the reporting GWP. Always document which IPCC report you used.

Refrigerant	100-year GWP (AR4)	Typical use
R-32	675	Domestic air conditioning and newer-generation split units
R-134a	1,430	Commercial refrigeration, vehicle air conditioning
R-410A	2,088	Air conditioning and heat pumps (a blend of R-32 and R-125)
R-404A	3,922	Commercial and industrial low-temperature refrigeration
R-744 (CO2)	1	Low-footprint commercial and industrial refrigeration, the scale's reference point

Documenting it for verification

When the audit comes around, the verifier does not ask how much the refrigerant line item emitted: they ask where each kilogram comes from. A solid file includes, per installation, the equipment's technical sheet with its nominal charge, the period's service reports, the outcome of leak checks where the regulation requires them, the calculation criterion chosen (mass balance or leak-rate factor), and the source and year of the GWP applied to each refrigerant. If a unit changed refrigerant during the year, for example through a retrofit to a lower-GWP gas, flag it explicitly: it is a change of method you need to be able to explain, not an anomaly to hide.

Frequently asked questions

Are fugitive refrigerant emissions always scope 1?

Yes, when the company itself operates the equipment: they are direct emissions under operational control, per the GHG Protocol. If a third party manages the equipment in a leased facility, you need to document who holds operational control to decide whether it belongs in scope 1 or scope 3.

What if I don't have refill data from previous years?

Use the leak-rate factor by equipment type for the current year, and document that it is an estimate while you set up the maintenance record that will let you switch to mass balance the following year.

Does every air-conditioning unit need a leak check?

No. Only units above the 5-tonne CO2-equivalent charge threshold, unless they are hermetically sealed and labelled as such below their own exemption threshold.

Which GWP should I use, the regulation's or my reference emission factor's?

To comply with Regulation (EU) 2024/573, use the one the regulation itself sets (AR4 for HFCs). For your sustainability inventory, use whichever your reporting standard requires, and always note the source, since they may not match.

How long do equipment records have to be kept?

At least five years, under the article of the regulation dedicated to equipment records.

Reconstructing this line item equipment by equipment, with the source document behind every figure, is exactly what our carbon footprint solution is built to do, connecting the service report to the scope 1 inventory without a separate spreadsheet.