Product review (5 stars): A great source of moist, warm air during Winter in the Great White North
I had one of these over 20 years ago when we lived in Iowa, but had been unable to locate one in any of the local stores since moving to Idaho.  To me, it doesn't make sense to run a furnace with a humidifier in one end of the house and then pipe all of this warm, moist air outside at the other end. Excessive humidity in the house is never a problem in this neck of the woods, especially during winter.  Do not use with a gas dryer though because the carbon monoxide could kill you.

Two problems, both of which are simple to solve: First, the screen on the exhaust fills up rather quickly with dryer lint.  Simply cut the screen out and mount a nylon stocking over the hole.  Now you have a superior filter that can hold large amounts of dryer lint safely.  Second, the unit has no plate for mounting it to the wall.  I used some wall anchors that you attach cable ties to, and it worked just fine.