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Controlling cellar humidity with an automatic window opener

I’ve been kicking around an idea about controlling the humidity in my cellar by automatically opening the cellar window when the absolute humidity outside is lower than the cellar humidity.

Has anyone done this? Hardware?

Any tips welcome.

Regards

Jeff

I’m not so sure that would be effective. In general, the strategy for lowering basement humidity is to seal it up, insulate if practical (Closed cell foam), and use mechanical dehumidification.

If you are inclined to bring in outside air, you might consider doing so only when the surface temperature of the walls and floor is greater than the dew point of the outside air, which is rare in the non heating season. The air temperature of a typical basement is above the surface temperature of the lower walls and floor, and so the relative humidity, which is a function of temperature, will not be an effective proxy for the potential of condensation of the ventilation air.

If there is bulk water infiltration, any ventilation will probably be futile.

The air temperature of a typical basement is above the surface temperature of the lower walls and floor, and so the relative humidity, which is a function of temperature, will not be an effective proxy for the potential of condensation of the ventilation air.

Absolutely, which is why it is important to use the absolute humidity. As long as the absolute humidity of the outside air is lower, then it is fine to use it for ventilation. Unfortunately in summer, the best time to do this is often in the early hours of the morning, when I don’t want to open the windows manually.

Home Assistant, Sonoff, ESPHome or Tasmota.

Home Assistant, Sonoff, ESPHome or Tasmota.

Good tips, thank you.

However, what I really need to get me going is a suggestion of suitable motor that I can control with one of the above or OpenHAB.

I don’t know what power source you have but could you use a servo motor from a model aircraft. I have a prototype button actuator using an ESP. At the moment the ESP is connected to an arduino pro mini that controls the servo. Servos are available with very high torque.

I’m considering something like this, which would use mains 230V. I’d probably have to design a circuit to allow a switch to manually override the input from the RPi:

https://www.attasshop.de/antriebstechnik/fensterantriebe/klappfenster/fensterantrieb-liwin-fuer-kipp-und-klappfenster-350-n?number=410001

instead of opening/closing window why not build yourself a humidex/ez-breathe. which is basically fan system that pulls air off the floor of the basement… you end up with much healthier air in the basement with less mold and dampness. ( if the power consumption a concern then have the fans driven by a small solar panel) basically it pulls the heavy damp air out near the floor and warmer drier air is pulled down from upstairs into the basement
example :