In article , Tony wrote:
wrote:
I've seen $250 humidity detecting fans (Broan?). I have a timer on my bath
fans, and motion detectors on my hallway lights (installed when my dad was
dying), so I can't believe they can't make a wall switch which detects
humidity. ANyone see one? Couldn't find one with google. Besides the
bathrooms, I'd wonder if I can't have one for the house when I'm away and
don't want to have the heat or cool on just to prevent mildew. I hadn't used
cooling in years and the upstairs duct perspired onto my ceiling.

I bought 2 army surplus one years ago, high quality stuff! I used it to
totally rebuild a donut proofing box because none of the original parts
were available. (the donut proofing box circulates warm humid air
around the raw donuts so they rise without drying out). A fan, a
stainless steel container like in a salad bar with a generic water
heating element installed in it, the humidistat, and a larger container
of water to siphon water in the small "boiler". Sorry I can't recall
where I bought them.

Yes I probably bought the same ones years ago. Wrapped in sealed
bags. I just tried using one in my bathroom.
They are not reliable near the extremes. You cannot set it to 80 % hummidity.
The horse hair mechanism is too critical up there. I was able to set it
to about 60%, and one rainy day it just came on. i mounted it uo in the air
box which I had taken out the fan and used an in-line fan for noise control.Its
works OK with the Dew Stop condensation sensor,
but I really need more CFM.
Most mechanical sensors have the wrong connection for fan use.

greg