It's okay to use a fan or the AC at a certain temperature. Babies should not be overheated because it is a risk factor for SIDS so I would definitely use something.

I use our a.c. its central air so the whole house stays around 72° and my baby is still sweaty when we keep her swaddled up. Its better to expose them to cold and keep them warm with clothes and blankets than to have them be super hot.

I would use it

I had it on the first night she came home, they say to keep it 75-78 but once shes able to regulate her temp you can turn it down a bit and just make sure she has more layers

Fall asleep

If u have a fan turn it on the newborn fall easy with a fan on . So they won't get hot themselves either @ivette15martinez

I always have the AC on along with the fan on at night cause my bf sleeps hot, I have a 2 months old, even when she first came home. I always have two blankets on her at night. If she's wearing a onsie, I put socks on her. If she's not in a onsie she's in a sleeper. She hasn't been sick at all so far.