Daox's diy thermal differential controller

[mag7mm308]

How about using your idea to pull hot air in winter but instead of connecting a fan to attic connect to a duct vent in floor and pull cool air from basement for free air conditioning? Also for using your controller for solar hot water pump could you either make a small 5 volt solar panel to run adruino and 12 volt panel for pump then change switch to 12 volt? Or even use 12 volt panel and reduce 12 to 5 volt going to adruino so you only need one panel, If solar hot water panel is warm enough to heat water you will have plenty of sun to power solar panel and you would have a system that would heat in case of poer outage. Just ideas I have been working on for myself, really like your controller also thanks

[MN Renovator]

I did that until the basement was 76 degrees and I realized that it wasn't exactly free and the cool basement wasn't cool anymore. Works for a little while, maybe in the swing season for longer but no longer than a week. Neat backup plan for when the power goes out and your generator is 120v and can't power the a/c.