I am reposting a blog post from 4/9/10, which got lots of great feedback and I think is a helpful post. Here it is!
Today I had a query from my colleague, Donna Hamil Talman, who is about to install a ventilation system in her studio for the use of encaustic painting. I told her about the vendor I used, http://www.sanyangpai.com/ , where I purchased a fan about 2 years ago. The vent fan is much more powerful than what you'd buy locally, and it has a great warranty.

To install it, I built my version of a kind of Kool Aid Stand (above). The fan is suspended a couple of feet above my work table, which is at waist height. I can move freely around my palettes with the fan above my head. I have also installed a long ventilation hose, so that I can move the table in my studio space if I need to.
To pull the air out of my space, I installed a dryer hose from the fan to the window. I also usually open a window to help with the circulation.
It has been quite beneficial as I have moved to primarily using encaustic paint.
Also, if you want to read other info, look on the R&F Encaustic website