For years I've been looking and threatening to build my own but before I finally give up and cobble something together with a couple of thermocouples, a relay, a fan, and an Arduino:I live in eastern San Diego. It's never terribly cold (might hit freezing a couple times a year) and typically doesn't get above 95F in the summer. Very rarely above 100. My house doesn't even have air conditioning or central air, just a couple of natural gas gravity heaters which run sometimes in the winter. The house is well sealed and insulated which helps a lot.What I really want is a system which can detect inside temperature and outside temperature and if the outside temperature is closer to the desired 70F than the inside temperature to run the fan.The temp swing can be rather large from day to night so maybe have a minimum temp it would cool down to (60F) during summer and a max temp it would warm to (80F) during winter. Maybe get a little fancy and have some awareness of the previous day's high and low and if it got particularly hot during the day (summer), cool a little lower (run longer) at night if possible, and if it was particularly cold at night (winter) to warm a little more (run longer) during the day.Right now I open doors and windows at night, cool the house down as much as I can, then seal it up in the morning. This works great. Opposite in winter time.But it would be great to have a system to do this automatically. I can't believe nobody seems to make one.Anyone seen something like this? via /r/DIY https://ift.tt/2NEnzih
