(S40) Smart T-Stat 4+

The S40 replaced my old white Lennox thermostat that had a dead screen. S30 thermostat was discontinued and unavailable. My only complaints are the expensive $1000 cost, touch screen will not wake unless I wave my hand within an inch of the screen or touch it, and is not Apple Home Kit compatible. S40 works with Google Home ok but I don’t care to use Google Home. The Apple S40 app is designed to work specifically with this thermostat and is required to replace the old Lennox app to work with iPhones. The screen brightness is about right at the very highest setting at all times. The WiFi connection is much more stable than my old thermostat. The outside temperature can be set to display either the outdoor sensor temperature or the local Accuweather temperature.

This thermostat and app are terrible. In fact anyone considering the purchase of a Lennox AC would be well advised to thoroughly investigate the thermostat first. It might be enough of a deterrent to redirect your choice of AC units. We have found our thermostats to not be accurate on temperature measurement and hopefully can be recalibrated. The thermostat does not always accept and keep the temperature that is set for control. Also, we have seen the app display one room temperature only to have it immediately jump to a different temperature when we go to make a control setting change on the app. We just had 2 new AC units and corresponding thermostats installed 2 days ago. I do not believe these opinions are based on an unfamiliarity with the thermostats as we previously had the previous but similar S30 version on our older Lennox units.

Update - after about a month my feelings are almost the same. Learning to live with this garbage. Why do companies think they have to fix things that aren’t broken? This ‘new and improved’ thermostat was about like the message you get when you open an app - “you have an update”.

This thermostat does what it’s supposed to do well, in the sense that it will make the temperature in the house warmer or cooler. However, I have two issues with it. One is just a matter of getting used to in that the temperature of my house feels two degrees cooler than what the thermostat displays. I solved this problem by adjusting the setting up by two degrees.

The lack of a vacation mode is more problematic, and this matters less on departing than on returning home. It can take a solid 24 hours to bring the house to the right temperature after a trip. In winter I set it to 55 degrees and in summer I set it to 85 degrees. I want to program the heating or cooling to begin the day before I get home and to set this up before I leave. I don’t want to have to remember to pull out my phone to adjust this a day before returning home. It should be automated and that’s easy enough to program, but it does not allow this unfortunately. I hope this becomes possible in the future!