Cello

Initially, I wanted to use the POW R2 just for the measurement. It would never do the switching, as I use a Geyserwise for that. After playing with HomeAssistant though, I'm going to give it a go. Based on what I've read here, I'll rather attempt the following: Use a Sonoff Basic, flashed with Tasmota Use the Geyserwise thermometer attachment as input to measure the temp Use something like this (https://www.netram.co.za/1128-30a-max-non-invasive-ac-current-sensor.html) connected through a voltage divider to another GPIO input (maybe the button, as this won't be needed anymore) to measure current Some 30A relay mentioned in the post so far to do the actual switching Schedule the on/off times and max temp with HomeAssistant Should be a nice little project, as this would allow you to: Define a schedule via HomeAssistant Define a maximum water temperature Change the schedule of the heating based on other inputs, i.e. temperature outside, seasons, sunset/sunrise, number of people at home (through presence tracking) Remote control Report on the power draw