"Last Reset Missing" On Summing Helper Entity

[terse otter]

My Emporia Vue 3 is using two clamps to measure the Tandem breaker for my air conditioner. To combine them, I created a Helper entity to sum together Living Room A/C 1 Daily Power and Living Room A/C 2 Daily Power to the entity Living Room A/C 1+2 Daily Power, measured in Wh.

I've added this entity to the Energy dashbaord, but it gives two errors:

1. Unexpected device class : The following entities do not have the expected device class: sensor.living_room_a_c_1_2_daily_power
2. Last reset missing : The following entities have state class measurement but last_reset is missing: sensor.stove_1_2_daily_power

Through the ESPHome web interface, I can see it is currently using 836.9W on the first circuit and 4.4W on the second.
In the Home Assistant Energy dashboard, both circuits are showing 0W of use

[hard plaza]

You can't add power sensors to the energy dashboard

You need energy sensors

[terse otter]

Oh shoot, the names of the sensors are wrong but they are energy

The combined sensor is Wh

[hard plaza]

But your sensors also show power?

[terse otter]

Yeah I just screenshoted the wrong section

Sorry for the confusion

[grizzled perch]

You can't really sum energy total sensors and get good behaving results.

maybe it works if they never reset, but it won't work with anything that resets

[terse otter]

What's the best way to get this into the energy dashboard then?