Aube / Honeywell Thermostat Smoke Stains - Solved


Old 12-19-20, 08:39 AM
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Aube / Honeywell Thermostat Smoke Stains - Solved

My home is heated with electricity and we have about ten of the Aube/Honeywell thermostats with the proportional sensing feature. They are all leaving these stains on our walls. I think I have come up with a simple fix for these, but before I explain it, let me say that these are excellent thermostats and will keep a room at a perfectly stable temperature. The "smoke stain" is not from smoke. The stain comes from the electrostatic effect of warm air from the thermostat drifting up the wall. The source of the heat is a resistor (I think it's a resistor) inside the thermostat that stays quite warm all the time unless the circuit breaker is off. (We shut off our electric heat in the summer.). Nothing is burning and there is no risk of fire.

The cure for this is simple. First, clean the wall. Soap and water usually is not enough. A Mr. Clean Magic Eraser does a good job on painted walls. Now find an old HDPE milk or water jug. Clean and dry it. Cut out a curved part of the bottle, like at the bottom, in a strip about 1" wide and 2" long with the curve at about 1 1/2" up on the long side. Carefully slide this piece behind the thermostat, between the thermostat and the wall, on the top right side of the thermostat where the smoke stain originates. This will divert the warm air away from the wall enough that the air will cool sufficiently to not trace up the wall.

No more smoke stains. Perhaps Aube/Honeywell will consider building a little deflector into their plastic housing.


Last edited by omero; 12-19-20 at 08:43 AM. Reason: correct images
Old 12-19-20, 03:28 PM
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Is the wall sealed behind the thermostat? I've seen similar issues where convection is pulling air from inside the wall (from the basement of attic) into the room, and along with the air, whatever dirt and dust is in the wall/attic.

Sealing the hole helps reduce air and dust coming in - and will also keep the temperature more accurate.
Old 12-21-20, 12:41 PM
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Hi, just curious, what is the model # of that Stat?
Geo 🇺🇸

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