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Refrigerant & air-con leaks carbon calculator (Scope 1 fugitive emissions)

Turn kilograms of refrigerant refilled into Scope 1 kgCO2e using EPA GHG Emission Factors Hub GWP values for six common gases — free, with full provenance.

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How this calculation works

Refrigerant emissions don't come from combustion — they come from leakage. Cooling systems and electrical switchgear hold a sealed charge of gas that slowly escapes through fittings, seals, and valves over years of use. That escaped gas is a direct, uncontrolled release straight into the atmosphere, which makes it a Scope 1 emission: a source your organization owns or controls, just like a fleet vehicle or a boiler.

Emissions (kgCO₂e) = kilograms refilled × Global Warming Potential (GWP) of the gas

The formula looks like the fuel calculators, but the numbers behave very differently, because refrigerant GWPs are enormous compared to a combustion factor. Burning a litre of diesel emits about 2.7 kgCO₂e. Losing one kilogram of R-410A is equivalent to 1,924 kgCO₂e — roughly what 700 litres of diesel would emit. A leak measured in single-digit kilograms can rival or exceed an entire building's annual electricity footprint, which is why this category deserves its own calculator rather than a single line buried in a bigger form.

Why refilled kilograms stand in for leaked kilograms

Nobody weighs the gas as it escapes. Leaks happen slowly, through fittings, worn seals, and vibration-loosened joints, over months or years, and by the time anyone notices reduced cooling performance, the gas is already gone. What can be measured is the opposite side of the same transaction: how much fresh refrigerant a technician had to add to bring the system's charge back up to spec during a service call.

Over a maintenance cycle, refilled quantity is the standard, defensible proxy for leaked quantity. If a chiller needed 2 kg of R-410A topped up during its annual service, the working assumption is that roughly 2 kg leaked out since the previous service — the system's total charge is fixed by design, so a top-up close a genuine gap, not a discretionary addition. This is the same logic environmental regulators and GHG Protocol guidance use for the "screening" or "material balance" approach to fugitive emissions, and it is exactly what a refrigeration or aircon service invoice records: gas type, kilograms added, date, and technician. That invoice is the document this calculator is built around.

The gases and their GWP factors

| Gas | GWP (kgCO₂e/kg) | Typical use | | --- | --- | --- | | R-32 (HFC-32) | 677 | Newer split-unit aircon | | R-134a (HFC-134a) | 1,300 | Chillers, some vehicle AC | | R-407C | 1,624 | R-22 replacement, older systems | | R-410A | 1,924 | Most modern split and packaged aircon | | R-404A | 3,943 | Commercial and cold-chain refrigeration | | SF6 (sulfur hexafluoride) | 23,500 | Electrical switchgear insulation |

All six factors are 100-year GWP values on the AR5 basis, published by the US EPA's GHG Emission Factors Hub (2025 edition) and released as public domain data. Notice the spread: SF6 sits more than an order of magnitude above the refrigerants, and even within refrigerants, R-404A is roughly six times R-32's factor for the same kilogram lost. Knowing which gas is in which system changes the answer enormously, so check the nameplate or service record rather than assuming.

SF6 belongs to switchgear, not cooling. It is included here because it is the highest-GWP gas most organizations will ever handle, and because electrical switchgear maintenance produces the same kind of top-up invoice as an aircon service. Any organization running medium- or high-voltage switchgear — a data centre, a manufacturing site, a campus substation — should check whether its maintenance contractor tracks SF6 handling, because even a fraction of a kilogram can be a meaningful emissions line.

A worked example

A mid-sized office building's annual aircon and switchgear maintenance turns up two service invoices. The chiller service shows 2 kg of R-410A topped up. A separate switchgear inspection shows 0.1 kg of SF6 handled during a gas-handling procedure.

R-410A: 2 kg × 1,924 kgCO₂e/kg = 3,848 kgCO₂e

SF6: 0.1 kg × 23,500 kgCO₂e/kg = 2,350 kgCO₂e

Total = 6,198 kgCO₂e ≈ 6.2 tCO₂e

That 0.1 kg of SF6 — a tenth of a kilogram, barely a cupful of gas — contributes over a third of the total. This is the pattern that catches most organizations off guard: refrigerant and insulating-gas leaks are physically tiny but carbon-dense, and skipping this category because "it's just a top-up" can leave a real gap in a Scope 1 total.

What this calculator doesn't cover

  • Vehicle air-conditioning. Mobile AC refrigerant is Scope 1 too, but it's serviced on a different schedule from fixed installations — track it separately from building and process refrigeration, alongside the fleet fuel calculator.
  • Clinical and process gases without open factors. Some specialised refrigerants and process gases used in healthcare or manufacturing don't have a publicly licensed GWP factor in this registry yet. If your invoice names a gas not listed above, note the quantity separately — omitting it understates your total.
  • Gases outside the six listed. R-22, propane (R-290), isobutane (R-600a), and various proprietary blends exist and have published GWPs, but aren't yet in this tool's factor set.
  • Full charge inventories. This calculator estimates leakage from top-up records, not the total refrigerant bank in your equipment — a full inventory-based method (used for regulatory F-gas reporting in some jurisdictions) is a different, more detailed exercise.

None of these gaps make the top-up number wrong; they define what it estimates — leaked refrigerant and insulating gas inferred from maintenance records, for the six gases with open-licensed factors.

Where this fits in your reporting

Refrigerant and insulating-gas leaks are Scope 1 — direct fugitive emissions from equipment your organization owns or operates, alongside fuel combustion. The kilograms-times-GWP arithmetic feeds the same total whether the equipment sits in a company's server room, a nonprofit's walk-in fridge, a school's air-conditioned hall, or a public agency's substation, and it counts toward whichever framework asks next — ISSB IFRS S2, GRI 305, or a CDP fugitive-emissions line. Singapore-listed issuers have their own timeline for when Scope 1 becomes mandatory in filings — see the SGX climate reporting deadlines guide if that applies to you. If you'd rather not read the invoice by hand, upload the service invoice itself and let the same factors apply automatically, with a confidence score on every extracted figure.

Sources

Frequently asked questions

Why does the calculator ask for kilograms refilled, not kilograms leaked?
Because leaked refrigerant is invisible — it escapes gradually and nobody weighs the gas as it goes. What every refrigeration or aircon service invoice does record is how much fresh gas the technician topped up to bring the system back to its charge. Over a maintenance cycle, refilled quantity is the standard, defensible proxy for leaked quantity: if the system needed 2 kg to top up, roughly 2 kg escaped since the last service.
What is GWP and why does it matter so much here?
Global Warming Potential is how many times more warming a kilogram of a gas causes than a kilogram of CO2 over 100 years. Refrigerants have enormous GWPs compared to fuel combustion — SF6 is rated at 23,500, meaning one kilogram is equivalent to over 23 tonnes of CO2. That is why a small refrigerant leak can outweigh an entire year of a building's electricity bill, and why it is worth tracking even though the physical mass involved is tiny.
Why is SF6 listed here when it's not really a refrigerant?
SF6 (sulfur hexafluoride) is an insulating gas used in electrical switchgear, not cooling systems — but it belongs on this page because it is the highest-GWP gas most organizations will ever encounter (23,500) and because, like refrigerant, it shows up as a top-up quantity on a maintenance invoice. Any organization with medium- or high-voltage switchgear should check its maintenance records for SF6 handling before assuming this field doesn't apply.
Is refrigerant leaked from company vehicle air-conditioning covered here?
No — mobile air-conditioning refrigerant is technically Scope 1 fugitive emissions too, but it needs its own service records separate from building and process refrigeration, and this calculator's proxy method assumes a fixed installation. Track vehicle AC refrigerant separately if your fleet has it serviced independently.
What if my system uses a gas not listed here?
This calculator covers the six refrigerant and insulating gases with open-licensed GWP factors in our registry: R-410A, R-32, R-134a, R-404A, R-407C, and SF6. Other common gases — R-22, R-290 (propane), R-600a (isobutane), and various blends — exist and have published GWPs, but aren't yet in this tool's factor set. If your invoice names a gas not on this list, note it separately; leaving it out understates your Scope 1 fugitive total.