I have a southern California two-story home built in the late '70s. It's a single-zone system with both heating and cooling. The thermostat is located downstairs. In the summer the upstairs gets too hot and in winter the downstairs is too cold.
I'd like to put a wireless second thermostat upstairs and pair it with the hard-wired one downstairs. That way the system can tell the actual max./min. of the house temperature.
Are there any thermostats out there to do this? Would it even work?