12W Always On from my HVAC system?

Hopefully it’s ok for me to enlist the collective intelligence of this community too :smiley:

I recently did a deep audit of my Always On devices while writing up this guide.

One mystery I stumbled across was my HVAC system.

Let me first give a quick breakdown: I have a heat pump that is on its own circuit. Then, I have a separate HVAC circuit which has my air handler for 10kW electric resistive heat strips and my Ecobee.

The mystery: On that HVAC circuit, with nothing running at all, I isolated ~12W Always On. Based on Ecobee specs, that accounts for 2-3W. So, what’s the other 10? I’m guessing it’s something to do with the furnace control board but what exactly?

I’m not expecting to eek further savings here, just curious at this point.

My furnace control board takes about 8W for each furnace (as measured by AN HS110 smartplug) , but that 8W includes the power supply for the corresponding Ecobee as well.

Not too far off from me. Guess it’s normal!

There is a dedicated transformer supply Snding 24 volts to your thermostat and the control board for the condenser and air handler.
This transformer Converts 120 or likely 240 down to the safer 24 a/c
But 12 Watts is normal

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