I'm trying to understand down fill power(450, 750, 800 etc) and the advantage in the size it packs down to.
At first I scratched my head, why would you pay $100's more for a sleeping bag to save just a few grams. Made no sense unless you had money to burn and then I thought, maybe the higher rated down takes up less space in your pack.
Does higher fill power mean less litres in size when packed?
If so, is there a rough ratio I can use to calculate this i.e: 800 will pack down 20% less than 700