Is it possible to aggregate Energy from many sensors?

So my house has 4 circuit breakers:

  1. Red - In the garage, for the garage opener, some receptacles and the EV car charger.
  2. Blue - First floor of the house, for common areas and kitchen (range, oven, microwave, coffee maker, dishwasher, fridge, etc.)
  3. Green - 2nd floor - Bedrooms, office with computers/NAS/router/UPS and laundry (washing machine/electric dryer)
  4. Pink -A/C mini split units (4) and water pump

So, while I could install a single, whole house monitoring system, it wouldn’t be as actionable as being able to monitor each circuit individually. However, solutions like Iotawatt aren’t designed to aggregate results from more than one unit. I was wondering if I could solve it this way:

  1. Use (1) Shelly EM in Panel 1 - 1 CT for the car at 240, 1 CT for the garage opener and receptacle at 120v. I’m selecting Shelly EM here because I don’t need so many CTs as with Panels 2, 3 and 4.
  2. Use (1) Iotawatt A in Panel 2 - 14 CTs are enough for this panel
  3. Use (1) Iotawatt B covering Panel 2 and Panel 3 (they are close together) -14 CTs should be enough for these to panels

In Home Assistant, I need Grid Consumption to be the sum of all sensors in Shelly EM + Iotawatt A + Iotawatt B. Is this possible? I am assuming that both, Shelly EM and Iotawatt will calculate correct consumption, corrected for power factor.


Yes it is possible. You can use a template sensor to do the addition.

Thank you. I’ll leave this example that I found for other people that like me have never created a template sensor. Please disregard the rest of the content of the page. You don’t need a Solar edge system to learn from this example. Of course, you need to replace the content of the formula.