I just install a 24k pioneer in my garage last week. 30x20x9
3 car garage, builder grade door insulation, no windows, no installation except for the wall shared by the house, and no attic installation. Keep it set to 75 and had no problems all week long. It got up to 100 this weekend so I was pleased. I was going to get an 18k but I'm glad I didn't. Once I add insulation, it's not going to be a problem.
I got the + not the ++.
Did you do the install yourself? just curious. I just ordered a 24K Pioneer myself yesterday. Hopefully it will be here in a week or so!!