Only One Vent Upstairs

[Elizabeth Zielinski]

I own a house and the landlord who sold it to me decided to put one vent for the entire second floor. There is also a weird vent that’s supposedly an intake vent (that’s what the inspector said) but it’s sealed off, so it’s more like a glorified hole in the floor. Any suggestions as to 1.) how to go about installing more vents or getting more heat/AC (I don’t want window units) 2.) what do do about the mystery intake vent/hole in the floor?

New to home/property ownership so any advice would be great! I eventually plan to move out and put renters in this place.