I only ever tend to run into exceedingly cold cabins. Good to know the opposite is a possibility too, and glad to have avoided it thus far.

I understand that not warming up the air beyond the bare minimum is a cost-saving measure. If cabin air is too hot then, would it mean that too much of it is being recirculated? Is there a lower limit (regulatory or otherwise) on how much % of the cabin air must come from the outside, or can the fresh air intake be set to 0 for the whole duration of a 10h+ flight?