Venstar T7900 ColorTouch Thermostat 7 Day Programmable w/ WiFi & Humidity (4 Heat 2 Cool)

I bought this for a dual fuel system because I could use the outdoor sensor to control the changeover temperature from heat pump to fossil fuel heat. The set up was flawed, somehow, because I initially couldn't get the changeover to successfully work without manually cheating the system. After several attempts to reset up the system, it is working now, and I wish I knew what I changed from the initial setup, but I don't. The energy tracking is very basic...just recording hours run time, with no inputs to convert to therms or btus. I was hoping for more capabilities. I would still recommend it to a friend. it is user friendly and much cheaper than other wifi capable t-stats. Not very many wifi stats are dual fuel capable. This was the only one I found for less than $200 that I could manually set the changeover temperature.

Humidity can only be changed from the settings menu and the API. There is no window frost control algorithm. There is no on/off control for a humidifier. The only reason I can see to buy this thermostat is the local API. I bought this thermostat because Apple Homekit does not enable non-cloud control of ecobee humidifier functions. If I didn't need to control humidity through the API I would be using an otherwise much nicer ecobee with Homekit for non-cloud control. On the positive side the Venstar API shows less noise in temp and humidity measurements compared to ecobee. The Trane XL1050, which I also use, also shows less measurement noise compared to ecobee. In my experience ecobee is more likely to unnecessarily cycle humidification and dehumidification equipment due to humidity measurement noise. Another downside of Ecobee is it requires the addition of a relay to control the air handler fan with a steam humidifier. Venstar has the proper fan option to avoid the need to add a fan relay when used with a steam humidifier. Venstar's cloud service seems well designed and useful with the exceptions of poor humidifier interface as noted. Enabling local control API does not stop the optional cloud service. I can only recommend the T7900 to a subset of users. It is physically an old school programmable thermostat with inferior polish and features compared to Ecobee and Nest. I'm using the T7900 with Home Assistant and have had no wifi or connectivity issues. It is 2.4g only and I have a separate 2.4g only SSID optimized for less capable IOT devices.