I sort of wish his air conditioner broke more often.
Why do you want his air conditioner to break?
Because he is so much more pleasant to be with when he is hot and sweaty.
Just because you enjoy being around him when he is sweaty doesn't mean he is comfortable that way. Have you talked to him about his mood when the AC is broken?
No, I don't like having to explain the reasons for my opinions to people.
Instead of wishing for his air conditioning to break so he is more pleasant, why not just talk to him?  If you let him know that you find him appealing when he is hot and sweaty, then maybe you can start working out together at the gym, which you would both enjoy.