Should a timer switch 'reduce' load?
Well...I typed that too fast, I guess. I just found the answer! Sure enough, this is not actually designed to handle fan loads. UGH. Just blew $40 on two of these. Apparently there's some small print. To quote a review on Home Depot's web site:


  Works great for lights,but as I'm finding a common problem with all electric supplies you must read the fine print. Huge voltage drop when I used it for my bathroom fan and as labeled in the fine print using it for a fan caused it to heat up. How it made a UL listing is beyond me. 


Sigh. Off to Home Depot to spend more money. This time I'll read the fine print...