I am George, the designer and developer of HestiaPi, an open source open hardware smart thermostat for your home.
It runs openHAB2 on RaspberryPi Zero with a 3.5" touchscreen, a BME280, 4 solid state relays and a range of input voltage from 24V AC to 100-240V AC. All that in a nice 3D printable case.
To make this come true we are running a crowdfunding campaign and we will be donating back to the openHAB Foundation.
Please check it out and pass it on.
It would mean a lot to us and the open source community if we can get a truly open product in the market against those consumerism giants.
Here is a press kit if it helps anyone with a blog.