At time of writing, there is no such thing as a 120V or 240V thermostat from any automation vendors – Insteon, Zwave or WIFI enabled. But it is still possible to control baseboard heat using automation thermostats.
Using your choice of low voltage automated thermostat, add a thermostat relay on the output of the thermostat, and a 24VAC power supply to run the thermostat. Some of the Aube thermostats combine this function in to one unit in to a relay that also provides power to the thermostat.
The relay can be installed near the thermostat if the high voltage wiring is already in this location and there is room for it – or it can be installed at the baseboard as they normally have a cover inside which it can fit. Just make sure to use one of the smaller relays if you are trying to fit in to a smaller space.
You need to verify the voltage and current load to confirm which is suitable and we suggest working with an electrician to ensure everything is installed safely and to code.
To power the thermostat, use one of the Aube relays with power transformer built in, or use a separate plug in power supply like TP2024 for example.
Relays can be found here: http://www.aartech.ca/thermostat-relays
Power supply can be found here: http://www.aartech.ca/tp2024-ne-plug-in-ac-adapter-24vac-20va.html