How do I count air conditioner and chiller gas top-ups in the Higg Facility Environmental Module (Higg FEM)?
Count the kilograms of gas you added to each machine in the year, since, in general, the Higg FEM guide treats gas added as gas released. Enter it by gas type, from invoices or service records. The form multiplies by its own warming figure, for example 1,960 for R-22.
What the guide asks
- Answer Yes if you track the quantity of all refrigerants used in all equipment on site. Answer Partial Yes if you track at least one but not all.
- The guide says refrigerants used within owned and operated vehicles have been in scope from FEM 2024.
- In general, it says the amount released equals the amount added to the equipment. Adding gas usually means the system leaks.
- Refrigerant purchase invoices or service records can help find the quantity released.
- For each gas it asks whether you added it in the year, how much, in what unit, how you tracked it, and whether you fixed the leak.
The warming figure the form uses
A global warming figure says how many times more than carbon dioxide a gas traps heat over 100 years, like a strength rating for each gas. In Cascale's FEM 2024 paper the kilograms of carbon dioxide equivalent (CO2e) per kilogram are R-22 1,960, R-410A 2,256, R-134a 1,530, R-407C 1,908 and R-404A 4,728. The paper says an empty factor value results in 0 kilograms of CO2e per kilogram of refrigerant.
If you want a leak rate
The guide's formula: kilograms added divided by the full charge, divided by days between top-ups over 365, times 100%. Its chiller example: 1 kilogram added, full charge 5 kilograms, 275 days, a leak rate of 26.5%, so about 1.33 kilograms lost in a year.
Two machines, one year
- R-22 split units: 12 kilograms added x 1,960 = 23,520 kilograms of CO2e
- R-410A chiller: 8 kilograms added x 2,256 = 18,048 kilograms of CO2e
- Total: 23,520 + 18,048 = 41,568 kilograms, about 41.6 tonnes of CO2e
- Leak rate check on the chiller: (1 / 5) / (275 / 365) x 100% = 26.5%
Quantities are an example. Figures are the FEM 2024 paper's and the guide's.
What Senseible does here
Senseible reads fuel invoices and electricity bills into monthly records. Senseible keeps refrigerant invoices as evidence but calculates no figure from them, so keep technician job cards with your own records.
Sources: Cascale, Higg FEM How to Higg Guide 2026 (English), Cascale, FEM 2024 Energy and Global Warming Calculations
Last reviewed 2026-11-07. Gas figures are from Cascale's FEM 2024 calculations paper; the guide text for step 3 of the leak formula reads differently from its example, so the example's formula is used. Check current tables each cycle.