I want dehumidifying mostly out of a central AC. I have a little 2-story house, with 660 sq ft on the top floor. The bottom floor doesn't get hot, it's half finished basement and half garage. I am running dehumidifiers down there though so that heats things up.
Right now I'm leaving the windows open at night, that and the ventilated roof keeps it fairly comfortable. But I would like to stop leaving windows open, and keep the upstairs dehumidified, which would heat it up a lot.
How could I get it sized right? I'm worried about getting it oversized and an automated kind of estimate from contractors. I read that Manual J is often oversized!