I have a south facing greenhouse attached to the side of my home here in Central Arizona. When I built the house I brought duct work in the floor over to the wall next to the greenhouse with the intention of scavenging heat out of the greenhouse in the winter time. The heat in the green house regularly gets to around 120 degrees and the high here currently is around 55 with a low of around 25. I have no idea of the heat that might come out of that greenhouse but the objective is to have the living room at around 65 degrees at the end of the day. It probably starts out in the morning at around 45 and finishes off at around 55or 60 when the sun goes down with no supplemental heat. Pretty cold in the morning.
The current idea is to install a bathroom fan near the ceiling of the greenhouse and blow what heat might come out into the floor duct to heat the living room - which is the first place the main duct comes through. Fan costs $15 at the local big box and a thermostat costs $20. Set the thermostat to cool so it comes on at say 100 degrees and I need it to go off when the temperature in the greenhouse drops a ways below that. The square footage of the greenhouse is approximately 125 sq ft and if there is too big a fan it will cycle way too fast. Therefor as a cheap experiment I was just trying to figure out how much difference a small fan would make before going in a little further.
Problem is the twenty dollar thermostat is not designed to turn on a 110 circuit. I need advise on what kind of thermostatically controlled switch might work here or some other solution. Any advice would be sincerely appreciated.