Before buying this switch I went through two Leviton IPHS5 switches (they do the same thing) both bought at Home Depot. I know electrical and yes, there were installed correctly. My Panasonic whisper fan (which starts slowly) simply didn't work. The fan would begin to spin slowly every few seconds, then cut off.

After failing with Leviton I switched to this product, hoping against hope it would work. I was not let down. This product worked perfectly the first time. Just slightly less important is the fact that this product is much easier to program than Leviton's version.

I strongly considered giving only four stars due to the wiring. This switch connects to Romex via stranded wire. There is no way to insert the Romex directly into the back of the switch. Perhaps this is just preference, but I have never liked threaded wire.

That said...I couldn't be happier. This product worked where Leviton let me down.

The media could not be loaded. I'm terms of functionality this is great. The humidity sensing is fast and accurate. The combo of a sensor with a timer button is perfect for my use case. You let the sensor work automatically for showers and press the button if you have to "take the browns to the Super Bowl". Additionally, the button and overall build quality feels solid.

I had a little confusion with wiring. The switch comes with 4 wires but my circuit only had three. What I saw on a YouTube video that worked for me was to connect both the white neutral and green ground to the copper ground in the wall. Then the red load from switch goes to the black hot in the wall and the black hot from switch goes to the white in the wall. I don't understand why this works but I won't question it.

And as people mentioned there is the issue that the automatic mode will be switched off if you manually turn off the fan however I see no reason to turn it off manually anyway.

Easy to install, though screws might be short

I like the streamlined packaging and the programming is done without taking the cover off. You program it by pressing the fan 8 times. Pretty easy, but only the option for high medium and low humidity detection. I don't think there is an option for how long the fan comes on. The programming instructions that came with the unit were confusing. I ended up looking online and finding more streamlined directions. It has a feature I do not like, because I am using this sensor in my vacation rental which is prone to humidity and therefore mold. If the fan is on and you over ride it by turning it off, it will never come on again unless you manually turn it back on. Maybe good for a homeowner, but terrible for a rental. I am going to have to uninstall it and install a different one.

The instructions appear to have been rewritten several times w/o proofreading by a knowledgeable person. First it says "There is only one Programmable Function" Then "Function 1: Humidity Level" , but then it talks about a time setting. Then in the Example, it calls Function 1 "Time Delay". (I think they mean Run Time). So 2 Functions are being mentioned. On the instructions flip side, it states "The fan has only one setting...20 minutes...". Ok, where's reality?
IMHO, the run time function is a vestige left over from a previous model, and got left in due to inadequate procedures.