Hmm, another way to help you orchid roots hold some moisture is to put some sphragum moss on them. It helps to retain some moisture and is pretty cheap.
Also, I bought a little mini-mist fogger from the people at Orchids Limited. I put it in a small bowl by my orchids and it helps by making fog and spits a little bit of water up too. I also put some plastic around my orchids too to help keep the humidity higher. Orchids Limited's website is here:
Orchids and Orchid Supplies (this was a little more expensive about $50 US).