Nice greenhouse. I have a similar one only a bit longer. I ended up with fans on both ends and after five years of fighting it getting to hot I finally installed a top vent. I turn things on and off manually and have doors on both ends. Keep an eye on the heat, you can always add fans and vents as you go. I think I've finally got mine working properly. A greenhouse has it's own set of challanges for the gardener.
