R290 has a GWP of 3.3, so that's 3.3x worse than CO2 with a GOP of 1. Which makes sense, because when propane breaks down it usually breaks down to CO2.
Thanks for sharing that portable AC's in Europe are R290, I don't think that's super common in the US. But I'm open to being shown wrong on that!
Thanks for sharing that portable AC's in Europe are R290, I don't think that's super common in the US. But I'm open to being shown wrong on that!