Product review (4 stars): Buy an extra valve to save water
The humidity in my house was always about 20%...rarely 22%.  After this install we are at 38% and could go higher if I wanted to.  Honestly, there's a youtube video of how to install this...its way easier than reading the instructions.  The vacuum hose that goes to the little white switch was backwards of what they said.  I thought it was broke and swapped the black/clear hoses around and bam, it fired right up.

The solenoid will turn on and off to save water while running.  However, it will still drain A LOT of water while it is on.  The key here is to install a valve on the water supply hose and limit the amount of water that can flow in.  I have no doubt that I have cut about 80-90% of the water waste!!!!!  I have a 95% furnace with variable speed fan, and the water is adjusted to where it just BARELY drains any water when on full speed.  As long as it's draining water, it means the waffle pad (the thing that the air passes through to get water into the air) is fully saturated.  Even when on low fan, it drains drastically less than before.  I know it's still working fine because otherwise I wouldn't be near the humidity levels I see now.

Wear gloves when cutting the holes or you might get torn up...also be aware you'll have to find a way to drill a 3/4" hole for a rubber grommet that the sensor needs.  I had a 1/2" bit and...well...lets just say it was interesting getting it to 3/4...For the big rectangle hole, I actually cut a smaller size, then bent the edges back toward the inside to the actual size, so the edges of the hole are bent metal instead of sharp edges.  Probably took about 2 hours to install.  A metal cutting disk on a dremmel would have been way faster probably.

The reason for 4 stars is the instructions really aren't that clear...they don't even tell you to put the rubber piece in the "saddle" clamp when installing it to puncture a hole in the water line.  It would be quite the show without it.

Overall it's a drastically better feeling house at around 40% humidity and has really stopped the "dry nose" morning...I'm sort of amazed at how different the house feels.  I didn't expect it to make much difference.