Lux Geo WiFi Thermostat · Is your wiring compatible with ... · Ecobee3 lite. If you want a smart thermostat, but do not want to hassle with a c-wire, here are the top options worth considering for your home. by side comparison ...No “C” wire? No problem. Find out how to install your new Wi-Fi thermostat without C wire, and learn more about why most models require a common wire. Smart thermostats are available that do not require a C-wire at all. But, not everyone can afford to replace an entire heating and cooling system.