Last summer was my first attempt at greenhouse gardening.
We had a tough time with heat build up. Some days the temperature would go over 105. We added a fan on a timer, and also misters.
Eventually we also put shade screen on the south end, where the sun beat in.
This year, we want to put in an exhaust fan. The greenhouse is about 1600 cubic feet. Reading on the fan websites, they say we need a fan that will replace the air in the house in one minute. Without spending an arm and a leg, we can get a 14" fan, that moves 1400 cfm.
We can get a smaller fan with just under 900 cfm.
1400 seems a bit strong.
Does anyone have any experience with exhaust fans and is it really necessary to have one as big as 1400 cfm?