My house has a crawlspace and I want to put an exhaust fan in one of the vent panels to pull air through the other vents. I can buy fans that can be turned on by temperature and/or humidity but I don’t want the fan to turn on if the humidity outside is higher than that in the crawlspace. I’m thinking I need just a basic fan that I can plug in which can controlled by a smart outlet that’s near it in the crawlspace.
I push data from my weather station to Weather Underground so I can get the local humidity using a WU API. I’ll need a device that reports humidity that I can place in the crawlspace, probably reasonably close to an access panel because batteries will need to be replaced.
I’d like to create a routine that polls the crawlspace humidity sensor on a schedule I set and if the humidity is higher than a threshold and the outdoor humidity is lower, run the fan. Then turn the fan off after a specified time period or when the crawlspace humidity gets below the threshold.
Does anyone have any suggestions about the best way to implement this and about a humidity sensor?