Meet the HestiaPi Touch: an open source thermostat that can be used to control your HVAC system in a smarter fashion. It comes with a Raspberry Pi Zero W, WiFi, and Bluetooth. The unit also has a 3.5″ touch display and temperature/humidity/pressure sensor.
The HestiaPi Touch comes with OpenHAB 2 pre-installed. It is compatible with iOS, Android, and Windows devices. It works with Google Home and Amazon Alexa. The enclosure is 3D printed.