I noticed this project on Kickstarter which repurposes your old smartphone into a smart thermostat: https://www.kickstarter.com/projects/1193751565/bemo-smart-home-system-and-smart-thermostat-altern?ref=recommended
I don’t know much about it but it’s an interesting take on a smart thermostat.
With zigbee connectivity, it can actually be an open source alternative to the smartthings hub. With added features such as having cellular and sms fallback capabilities (smartthings doesn’t work when your wi-fi or ISP are not connected).
The BEMO device also makes emergency 911 calls and has customizable looks and programming. Its really a smart thermostat and smart home hub all in one.
It includes 24/7/365 battery backup and all the features baked into your host device - www.bemo.io
Is it one of the paypal mafia team?