Heat is the same issue I'm running into, normally the basement is nice and cool (CAN keeps to a decent temp most of the year) but as summer approaches it's heating up fast! I can't do the window unit as the basement windows are too small...we'll see, thinking of reversible intake/exhaust fans in the windows to try and help a bit. Don't want to have to shut down the clients but it may come to that during the heat waves as the house doesn't have AC.