tennis wrote: > I have decided the practicality of having > a large exhaust fan on the roof is offset by the difficulty and will > probably go the standard route of vents and fans on opposite ends > of the GH at bench height
I don't think that is the standard route. More commonly, the exhaust fan is as high as possible in one end wall, and the vents are at ground level at the other end. That way you are exhausting hot air and pulling in cool air, and the air is circulating at all levels > My > question is this: when the fans kick on, as the peak vents will already be > open, am I not just pulling air through them down into the GH and not > from the opposing bench level vents which are further away A properly sized exhaust fan should pull much more air than can possibly flow through a couple of small peak vents, but yes, to some extent you will be short circuiting the system. Given the difficulty of building and properly sealing ridge vents, I just skipped them. If you are worried about power outages, you might consider a secondary solar-powered exhaust fan with a thermostat set a couple of degrees higher than your main fan. Charley's Greenhouse Supply sells them, and there are probably other sources. Since power outages in summer usually occur during thunderstorms (cloudy!), and overheating isn't a problem for me in winter, I decided that a gasoline-powered portable generator was sufficient for now. There is some risk of overheating if I don't get home in time to fire up the generator, but so far, so good. Nick -- Nicholas Plummer [EMAIL PROTECTED] _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
