Is there a straightforward way to add a thermostat to an existing (basic no-frills) whole-house fan? I'd like to be able to set it to shut off when the outside temp rises to a certain point–so that the fan shuts off automatically in the early morning.
A simple timer would probably be fine. Could the fan easily be wired to an off-the-shelf HVAC thermostat? (…and program the thermostat to turn off the fan at X a.m. if the indoor temp is above 0 degrees, say…) There is an existing central HVAC thermostat that could be replaced or added to if needed.
Best Answer
If you just want a timer, it's easy to buy a line-voltage timer switch that you can drop-in where the current fan's on/off switch resides.
If you want a thermostat, as the comments said you can find a line-voltage thermostat. THen you just need to run the hot feed from the on/off switch to the hermostat and then on to the fan.
Another option would be to use any low-voltage thermostat in combination with a 120VAC relay, but then you've got more parts, and need a low-V supply for the thermostat, so I wouldn't choose this option :-)