Open Energy Monitor is a system designed to allow householders to monitor their energy consumption including renewable sources such as solar and wind. In addition to the main unit it has several remote sensor nodes to measure temperature and relative humidity at a number of locations around the house. The version I have installed is based on a Raspberry Pi computer which is located close to the main electricity meter. The RPi uses Wi-Fi to communicate with the remote nodes and has a web-based interface so the data can be viewed anywhere.
