GWP (global warming potential)
Also known as: global warming potential, CO₂ equivalent
Short definitionA number that compares a gas’s effect on the climate with CO₂. It tells how many kg of CO₂ would warm the atmosphere as much over 100 years as 1 kg of leaked gas; 3,922 for R404A, 3 for R290.
The higher the GWP, the more each leaked kilogram of refrigerant warms the atmosphere. Carbon dioxide is taken as 1 and other gases are ranked against it: R449A 1,397, R134a 1,430, R32 675, R454C 148, propane 3, ammonia 0. The number only describes gas that escapes; the climate cost of the electricity the system uses is separate.
In a project, GWP drives the choice of refrigerant and the obligations of the operator. The charge in kilograms is multiplied by GWP to get the CO₂ equivalent: 10 kg of R449A comes to about 14 tonnes. How often leak checks are due depends on that tonnage. Gases above GWP 2,500 are banned in new systems, and below 150 counts as low GWP. When you name the refrigerant in a quotation, tell the customer which checks come with it.