Central AC breakers contributing to Always On

Hi all,

I had my Sense unit installed about 6 months ago, and I’m sure like everyone here, I’ve been experimenting with turning breakers off and on and watching my current energy usage. One thing that I noticed is when the breakers for my Central AC units are turned on (I have 3), my usage goes up about 80 watts per breaker and stays on even when my AC unit isn’t being used. Has anyone noticed this with their systems?


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It’s likely a sump heater that’s drawing that power. These are small resistive heaters that keep the compressor warm to prevent liquid refrigerant from pooling there when the unit is off. In my Trane unit, there’s a switch that cuts the heater off when the refrigerant discharge temp is above 80F.

If this is a straight-cool system (not a heat pump) then you should turn those breakers off at the end of the season so the heater isn’t drawing power all winter. Just be sure to turn the breaker on 24 hours before starting the system up in the spring, so the system has time to vaporize that refrigerant before the compressor starts up.

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i read this article years ago… i was fascinated. i turn off my heat pump breakers in the colder months when temperatures won’t allow it to draw enough heat.
“Central Air, turn off its breaker during colder months. My central air draws 33 watts all the time. I don’t know why. It doesn’t have to be running in the winter so when the fall, I turn its breaker off.”
in the article, he replaces door bell transformers and garage door transformer, which may never pay-off, but he set a goal and learned a lot.

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Thanks for the replies! It’s unfortunate that each of the zones adds about 80W each to my Always on by only flipping on the breakers, but it appears this isn’t an out of the ordinary trait for a Central Air system. The system is about 15 years old and I cringe looking at my Sense when the system is running (almost 6,000W), for the main house. More of a reason to invest in a newer, energy efficient system.