Hopefully not one of these captains that makes you sit in the airplane between flights (extended sits) with no air. Good way to add to fatigue and result in making a mistake and getting hung out to dry by FOQA. Save money sure, but don’t make your experience tougher at work to save a couple bucks.
There is still air without the bleed on.
I am sure you don't run the air conditioning/heating at home 24/7 if the temperature is nice and comfortable (about 20 degrees) so there is no need to do so at work.