Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Wren - Offset your carbon footprint by saving rainforests
ioBroker - flexible and modular application for the IoT and Smarthome
YAYZY - Track the carbon footprint of each purchase in real-time
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation
Klima - Go carbon neutral