Humidity sensor outside the bathroom (no air exchanger in the house)

I am trying to figure out the exact logic for installation of a humidity sensor/controller outside the bathroom + simple on/off switch inside (no air exchanger in the house)

I’m getting even more confused. I found those dials twice last months in a semi-detached houses an in the both cases there wasn’t any air exchanger, or HRV.

No owner to ask, eh?

Funny part - both cases the owner was there, but ignorant. :frowning:
One of the buildings was 15 years old, the other 25

Maybe just left over from an old air exchanger?

1 Like

The air changer or HRV were old, broke down and most likely were removed; the control was left behind. Any holes in the wall (air intake, air exhaust) left behind also?

That would explain it easily and quickly. However in the first case there weren’t any registers outside the bathrooms. In the second case there was only one in the kitchen.

HRV can be connected to the main plenum if there was a forced air furnace. What I meant when I ask if any holes in the wall (air intake , air exhaust) left behind, I meant the outside walls.

The first time i even went again on the attic, looking for signs for exchanger.

The owner said that it has something to do with the bathroom ventilator (it was on the opposite side of the wall with the bathroom fan switch), but we didn’t find how.

Did you check for a humidifier on the furnace?

No furnace, no air-exchanger, no heat recovery system, no vents in the bedrooms/living/dining room…

I see these quite often in mobile or modular homes and sometimes in condo units. In these cases the various bathroom fans, and sometimes kitchen exhaust, are all interconnected. The dial your are showing may be a dehumidistat. Turn it down, and all exhaust fans should kick in

1 Like

dehumidistat works almost like a humidistat but instead of closing, its electrical contacts open up when the room’s humidity level is lower than the controller’s setting. … The dehumidistat will then work to lessen the room’s humidity by removing extra humidity from the air.

So, if properly functional this dial can turn on the noisy bathroom fan in the middle of the night because of augmented humidity after light drizzle and wake up the occupants?

No wonder I’m seeing it only twice.

I had one connected at one time and removed it for that exact reason…

1 Like