How much air conditioning (AC) gas does a company car or bus leak in a year?

The Intergovernmental Panel on Climate Change (IPCC) puts a vehicle AC charge at 0.5 to 1.5 kilograms and its yearly operating emission rate (leaks plus losses at servicing) at 10% to 20% of that. That is about 0.05 to 0.3 kilograms of gas per vehicle a year, so the gas in the system matters most.

The IPCC default for vehicle AC

Table 7.9 of the Guidelines gives these ranges. A footnote adds that one study put leakage at 5.3% to 10.6%, and says those rates apply only to second generation vehicle AC installed in European models from 1996 on. The Guidelines say the lower end of the lifetime and emission factor ranges reflects developed countries and the upper end developing countries; choose within the range for your conditions and write down why. Charge and recovery have no such rule.

• Charge: 0.5 to 1.5 kilograms per system.
• Operating emission rate (leaks plus losses at servicing): 10% to 20% of the initial charge a year.
• Loss while the system is first charged: 0.2% to 0.5% of the charge.
• Lifetime: 9 to 16 years.
• Gas recovered at disposal: 0% to 50%.

Why vehicle AC leaks more than a building unit

• The Guidelines say vehicle AC is "subject to extremes in terms of physical shock and vibration and hence emissions tend to be large".
• The Guidelines say lifetimes tend to be shorter than many other cooling sub-applications.
• Because the charge is small, the Guidelines say recovery is "often seen as uneconomical and hence is not often practiced during service and disposal".

Charge by vehicle type

The Guidelines say small passenger cars will likely have lower charges than buses or larger cars, "especially those with multiple evaporators". Their worked example uses 0.7 kilograms for small to medium passenger cars and says its assumptions are for example only. Read the charge for each model from the maker's data and the gas from the AC label. Some newer vehicles use hydrofluoroolefin (HFO) HFO-1234yf, whose 100-year global warming potential (GWP) is 0.501 in the IPCC Sixth Assessment Report (AR6), against 1,530 for hydrofluorocarbon (HFC) HFC-134a.

Where it is reported

If you own or control the vehicles, HFC leaking from their AC is a fugitive release. The Greenhouse Gas (GHG) Protocol Corporate Standard lists HFC emissions from refrigeration and air conditioning use as a Scope 1 fugitive source for office-based organisations. Treating vehicle AC the same way is our reading. The IPCC itself does not use Scopes. Applying a national default to one fleet is our reading, so label the result an estimate and swap in gas charged at service as soon as the workshop records it.

40 cars at 0.7 kilograms each

• Gas in the fleet: 40 x 0.7 = 28 kilograms
• Yearly operating emission at 10%: 28 x 0.10 = 2.8 kilograms. At 20%: 28 x 0.20 = 5.6 kilograms
• If the gas is HFC-134a, AR6 (1,530): 2.8 x 1,530 = 4,284 kilograms to 5.6 x 1,530 = 8,568 kilograms of carbon dioxide equivalent (CO2e)
• Same range on the Fifth Assessment Report (AR5) value (1,300): 3,640 to 7,280 kilograms
• If the gas is HFO-1234yf, AR6 (0.501): 2.8 x 0.501 = 1.4 kilograms to 5.6 x 0.501 = 2.8 kilograms

The 40 cars and 0.7 kilograms are example numbers. Use one report, AR5 or AR6, for every gas in the inventory.

What Senseible does here

Senseible reads fuel invoices and electricity bills into dated records. It does not read recovery notes, service tickets or equipment nameplates, so keep those papers yourself and add the kilograms to your Scope 1 figure.

• AC gas a car workshop recharges
• Leakage without top-up records
• Bus operator emissions per passenger kilometre
• Free calculators

Sources: IPCC 2006 Guidelines, Volume 3, Chapter 7: Emissions of Fluorinated Substitutes for Ozone Depleting Substances, IPCC Sixth Assessment Report, Working Group I, Chapter 7 Supplementary Material, Table 7.SM.7, GHG Protocol Corporate Accounting and Reporting Standard (fugitive emissions in Scope 1)

Last reviewed 2026-11-05. Table 7.9 is a 2006 national inventory default, used here for one fleet as our reading. Prefer gas charged at service, and check the GWP set your buyer names.