Second affordable Thermostat that works with HA

New to HA, I currently have a Ecobee4 w/ Alexia (main floor). I want a second affordable thermostat for upstairs that I can control via HA. The currently issue I have is the baby sister have a penchant for leaving the A/C on up stairs when she is done baby sitting the baby. Which forces me to run upstairs and turn it off every time she leave. I will like to get a second thermostat that I can set to turn off once my motion sensor does not detect anything. I do not feel like giving up a kidney for a Ecobee or nest to accomplish this. Any suggest will be greatly appreciated.

Thanks in advance.

I have two I’m not using because I upgraded them to the color model with intermittent fan setting.

They go on sale every so often (Home Depot, etc)…or buy it used :slight_smile: Note: they do require a C wire for power…check before ordering or buying.

check ebay…lots available factory sealed…

works with alexa and/or home assistant.

Thanks and its also compatible with HA, great I will do my homework.
what the sales price on average?

So do you want a thermostat or do you just want to control the AC from home assistant? If it is ir remote controllable then a sensibo is a good idea.