Kevin, I think you're absolutely correct. Most of the books I read when I was coming along were for people with greenhouses. Even the Rebecca Northen "Home Orchid Growing" assumed that the home grower was using a greenhouse! And sadly, many of the newer books have just translated practices that were valid for greenhouse growing without saying much about the whys and wherefores. The worst reason (in my own orchid society) for using a fan I ever heard was because that's what they get in nature. What tiarella said about breaking up air and providing slight movement is very valid - no one contests that orchids dislike stagnant air. But there's a huge difference in fanning your growing area so the little leaves wiggle the way they tell you to do it in books, and providing a little gentle air movement in the entire room. This is why Jack Kramer suggested that natural currents would probably be sufficient. He seemed to understood our tendency to overdo. So truth be told I put a small circulating fan on unless humidity is really awful, but only to provide the slightest movement of air in the overall room. The higher the humidity the more air movement I provide. And in my space it almost never amounts to fans blowing directly onto plants or enough even to move the thinner leaves of an oncidium. What I do is suspend a length of thin twine over the edge of my light fixture, hanging down to the level of the plants. If that moves a little, that's enough air movement for moderate humidity. To see leaves move, you want humidity at least 60-65% I'd say. John

The ducts are not in the attic they are in the walls, and in CA we open all windows at night when it cools off a lot. Fans help circulate the air, and using the HVAC fan would blow more air around. It seems that when our furnace was installed they used old existing thermostat wires and the fan control is not hooked up.

Ok...did some more digging and I now know why the fan was trying to turn, hat case had become live and so it was acting as a neutral. I have never seen this before, is this common? All three wires have a resistance of 40ohms to the case, so what could cause that problem. Thanks, Neil

Other than simply location of the thermostat, it sounds more like you have too bid a swing temperature? Some thermostats have a setting that determines how narrow or wide the range can be- for instance, if you set the temp to 70, it will heat up to 72, turn off, then cool down to 68 before it goes back on. That is a 2 degree swing (above and below) giving your room a FOUR degree difference! If it were one degree swing, the difference would be 69-71 for a 70 degree setting. I personally find even a 1 degree swing noticeable as I tend to be cold. It is normal that you would totally sense a different comfort level with a wider swing. The smaller the swing, the more your system will cycle on and off to maintain the tighter temp range. Some thermostats are only one setting, though, so you have to look at the manual for yours. I think that is the most likely thing, but I am by far no expert. and yes, the celing fans help keep the hot air off the ceiling during winter when run in reverse on slow- especially good for those vaulted ceilings.