Should I put up a fan?

[prc11]

One year ago, exactly, growing orchids as a hobby began for me. Before than I had one Phal. and a small cattleya seedling I got at Lowe's. A year ago I visited a man's greenhouse and he showed me all of his orchids. He also gave me many to help me expand his collection. Since then I have obtained abut 40 more from evey where I can find them and they are living happily in my bathroom.
When I receive an orchid, I always do research on it to figure out its specific culture. However, the section I always seem to ignore is air movement. Since I grow in a small space, I didn't really plan on putting a fan up. However, I do not have a whole lot of humidity. I am planning on have the window open as much and as wide as I can this summer, which I hope will provide both humidity and air movement. When I first started growing I had problems with rotted roots, but now I seem to struggle less with that. Anyways, would it be a good idea to place a fan in my growing area this summer and at what strength and size. Finally what is your experiences, I know many of you have fans so how do they help your plants?