Hello Chip! Thank you for reaching out to us, this Smart Color WiFi Thermostat is not compatible with temperature sensors, however it is compatible with 24 VAC heat. You will have to make sure that you have a C wire to power-up the screen. To make sure that this thermostat is compatible with your system we would need to know how many total wires you have and which terminals are being used in the current one. At your convenience, please contact us at (855) 733-5465 Monday-Sunday 7 am to 10 pm CST and reference case number 01025754, we will be happy to verify the compatibility of the system-thermostat and provide you instructions to get a C wire in case tat you don;t have one. Have an excellent day!