Some thermostat makers, like Ecobee, Google, and Honeywell Home, make an adapter for their smart thermostats to add a C-wire, and sometimes sell it with the thermostat.

Some thermostat makers, like Ecobee, Google, and Honeywell Home, make an adapter for their smart thermostats to add a C-wire, and sometimes sell it with the thermostat.

If you're lucky, you already have a C or "common" wire to power the thermostat. If not, read my full review of the Honeywell Wi-Fi Smart Thermostat for more details.

The biggest hurdle for seeing if a smart thermostat is compatible with your home is the presence of a c-wire. Here's how to find it.

If you have or are looking at a Honeywell thermostat, check out the Honeywell THP9045A1023 Wiresaver Wiring Module (Fig. 3). It uses the “K” terminal on thermostat, which winds up controlling ...

WeatherBug Home and Honeywell Enable Smart Thermostat Users To See How Weather Impacts Their Energy ... Business Wire) Honeywell works with WeatherBug Home (Graphic: Business Wire) Full Size. Small.