Humidity controller in a closet

[Purfle Haze]

With two weeks of single-digit temperatures in the Northeast, my small evaporative room humidifier hasn’t been able to keep up. So I put two wooden guitars into a clothes closet with the humidifier. The closet space is only about 14 square feet/112 cubic feet, and now the humidifier was over-humidifying, reaching 60-65% RH on its lowest fan speed. This humidifier doesn’t have a hygrometer/controller; it’s either on or off.

Inspired by another thread on the forum, I bought this controller to turn the humidifier on and off.

I plug the humidifier into the controller, and plug the controller into the wall outlet. The controller has a cable with a humidity sensor on the end of it. I set the controller’s lower level to 45%, and the upper level to 50%. The controller turns on the humidifier when the RH drops below 45%, and turns it off at 50%. I have an independent hygrometer in the closet which I calibrated with the salt method. When I check the closet, the RH is always right around 47%. Pretty good!

The controller is easy to set if you read the instructions, and the sensor seems very sensitive; when I open the closet door, the RH reading on the controller’s display starts to fall right away. Not bad for $30. Odd installation observation: the controller has two slot-holes on the back to receive screws or nails so that it can be wall-mounted, which I did. The mounting holes are 3 9/32” on center. Why? Why not 3 8/32 (3 ¼) or some even metric measurement, like 8.5cm? Strange!

[guitar george]

That's great! Looks like you have the perfect solution.