[plonk]

> It emits about 4% of greenhouse gases [...] But the volume itself is not meaningful - the gases used by AC units are extremely powerful - up to 750 times the greenhouse effect of CO2.

Do AC units emit these gases? Aren't you mixing up CO2 from electricity production and gases that stay internal to the unit?

[bzxcvbn]

They have two types of emissions: CO2 emissions from electricity production, and refrigerant gases that are supposed to stay inside the unit. But of course, units have leaks.