Ken and Kathy, I should really stress the point that here in NJ I don't strive to cut the amount of sun light in the greenhouse, heh I grow my Orchids in Summer outside with minimum amount of protection for most of them. But Summers are simply hot here, we have lots of sunny days in the nineties, so I am looking to not cook the place, since it is part of the house. I switch off the air condition in the Summer in the greenhouse ( otherwise it would just stay on all day, that is not necessary, since it is empty then) but turn it back on in September for still occurring hot days.
My greenhouse is tied in with the heating and cooling system, Ken, but that fan still takes the top of the heat on warm Fall and Spring days, mostly. I have set it to jump on at 85 degr F.
It probably would have been a good idea to give the greenhouse its separate AC.
