Last summer we installed a 10" model. So far this winter, there have been no problems with condensation. The weather has been severe enough to test I'm sure. At the time, two were purchased but I've only installed one to test performance.The attic is a very shallow 4:12 and insulated with 6" of fiberglass.I would not hesitate to install the other, if we can find a good location in the bathroom.Incedently, if you do go with this product, optimize the need for light. I placed this one near a bedroom doorway to illuminate both the bedroom and a portion of hallway.We still find ourselves reaching for the light switch, thinking that a light is on! Great product.