Product review (4 stars): it works pretty darn well
I had one of these years ago when I lived in a large old victorian home in Iowa.  It didn't really do much to help heat the house and it introduced way too much humidity into the gas heated house.

Now that I'm in the Northwest, in a small house, with an open floor plan, and dry electrical heat, it works pretty darn well...

The added humidity is pleasant and the plants love it.  I'm heating approximately 1000sq ft and in about a half an hour after the dryer is running, the temperature in my back bedroom is up by 3 degrees.  I also bought some nicely scented dryer sheets and my entire house smells nice...

I wish I needed to do laundry more often since it really does make a positive difference...LOL

Only 4 out of 5 stars since construction is quite flimsy; but it was ten bucks...