I have a somewhat unusual situation, I think. I have a finished basement apartment in my house that I want to rent as a vacation rental. Until I can go the whole nine yards and install either a separate HVAC system for the basement apartment or a damper zoning system, I want people staying in the basement to be able to adjust the temperature of the HVAC system, basically overriding the temperature set on the main level thermostat.

I also want to be able to monitor and adjust the temperature of the whole house remotely from my phone or computer via a wifi connection, because we will be away much of the time until we move to the house on a permanent basis.

I haven't found anything that seems to do what I want. I am finding several options for wifi thermostats with remote sensors (Ecobee and Nest, and probably others), but you can't change the temperature up and down with the remote sensor. I have also found a non-wifi thermostat system (Venstar T1800 with T1119RF Add-A-Thermostat) that does exactly what I want, but it doesn't have wifi remote control. Basically, I would install the T1800 where the current thermostat is, and install the T1119 in the basement. Whichever thermostat is adjusted last controls the entire system.

Does anyone know of a wifi thermostat that has a second remote thermostat that can be adjusted up and down?