What do the terms in the refrigerant mass-balance equation mean?
Emissions equal annual sales of new refrigerant, minus the total charge of new equipment, plus the original charge of retiring equipment, minus gas destroyed. It is Equation 7.9 of the Intergovernmental Panel on Climate Change (IPCC) Guidelines, written for a whole country, so any company use is our adaptation.
The equation and its terms
Emissions = Annual Sales of New Refrigerant minus Total Charge of New Equipment plus Original Total Charge of Retiring Equipment minus Amount of Intentional Destruction.
- Annual sales of new refrigerant: all gas used to fill or refill equipment, at the factory, after installation or at servicing. It "does not include recycled or reclaimed chemical".
- Total charge of new equipment: the full charges of all new equipment. It does not include charging losses or gas used to recharge at servicing.
- Original total charge of retiring equipment: full charges of equipment decommissioned. It assumes the equipment was serviced right up to decommissioning and so held its original charge.
- Amount of intentional destruction: gas destroyed by a recognised destruction technology.
Why it works
Gas sold goes to grow the bank in use, to replace what was emitted, or to prime supply chains. The Guidelines leave stockpiling out of the equation and say terms for stockpiling and retrofitting can be added. The growth of the bank equals the charge of new equipment minus the charge of retiring equipment, so what is left of sales is emitted. It does not need an absolute count of equipment stocks or leak rates. Because it uses actual sales, the equation reflects assembly, operation and disposal emissions where they occur, and it avoids default emission factors, which the Guidelines say may be inaccurate because rates vary between countries.
Limits the Guidelines state
- It can underestimate emissions when equipment stocks are growing, because of the lag before servicing detects a leak.
- It is set at national level. We found no company version in the Guidelines, so say in your method note that you adapted it.
A site with its own gas records, one gas
- Virgin gas bought: 90 kilograms
- Full charge of new units: 40 kilograms
- Original charge of retiring units: 25 kilograms
- Gas destroyed: 0 kilograms. Emissions = 90 minus 40 plus 25 minus 0 = 75 kilograms
- If 10 kilograms of recovered gas is sent for destruction: 90 minus 40 plus 25 minus 10 = 65 kilograms
- Gas bought but still in cylinders at year end is stock, not use. Subtract the rise in cylinder stock from the kilograms bought (our adaptation); if stock rose by 5 kilograms, 85 kilograms enters the sum, not 90
All quantities are examples. Multiply kilograms by the global warming potential of the gas in one IPCC report for carbon dioxide equivalent.
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.
- Turn a top-up invoice into CO2e
- Gas left in scrapped cooling equipment
- Why top-ups understate leaks on newer units
Last reviewed 2026-11-05. Equation 7.9 is written for a country. Company use is our adaptation and should be stated as such.