How can I know if the thermostat I want to purchase is compatible with my heating and cooling system?

Please use the following compatibility checkers prior to making your thermostat purchase. Click on the link for the brand of thermostat you are looking to purchase to view compatibility with your system. Open box returns will not be accepted due to system compatibility issues.

Google Nest compatability checked can be found here.  
ecobee compatability checked can be found here. 
Honeywell Home compatability checked can be found here.
Emerson compatability checked can be found here.