Greenhouse: site for greenhouse., 1 by stressbaby

stressbaby wrote:
Hi guys,

The higher shutter is the exhaust fan. Low on the opposite end I have two motorized intake louvers. Also, I leave the glass up on the screen door in the summer. So the exhaust fan draws air from three points on the opposite end of the greenhouse. (See pic, w/ Dad since it is Father's Day!)

One person told me when I built that given my GH width, I should have two exhaust fans. By the time they told me that, I had already ordered and planned the whole thing out. Installing another fan is a pain with tempered glass, because you can't cut the glass, you have to special order it. I have one fan, properly sized, and so far, so good (knock wood/head!).

I think your orientation will be fine if it fits with the other factors and site properly.

Which direction is the GH in relation to your home? Prevailing winds from the north? Here, when it does blow from the north it is cooler and the exhaust fan isn't as likely to be on. It is the hot southerly winds that you don't want to fight with your exhaust fan, I would think. I would put the exhaust fan high on the NNE end and intake louvers low on the SSW end, drawing air across the length of the GH. I would increase by a factor of 1.5 or 2 the cfm result you get from the umass HAF formula for your HAF fans. Have you bought fans already?

SB