The video (not mine!) explains the settings of a similar system I am using. For more info, go to http://openenergymonitor.org/emon/
Other sites where I publish live data: http://daturach.github.io/
Using an ESP8266 ESP-01 module and an Arduino Pro Mini 3.3V I wirelessly update all outputs from my thermostat to here for data analysis and because it's cool.
This requires a voltage divided rectifier since thermostats run at least 24 VAC RMS.