Mystery Heat on at 12 hour intervals

Hey all. Does anyone have any idea what this mystery heat sense just discovered could be? It uses about 445 watts and comes on from 3:59 to 4:03, every 12 hours, occasionally skipping a time or two. I can’t for the life of me think what would use that much power at such precise times.The first image shows how many times it has come on since being discovered including the few times that it did not come on. The second image shows what a single time coming on looks like. The pattern is essentially identical every time it has come on so far. What could it be?

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Defrost heater in the fridge?


hmmm I hadn’t thought of that. I guess I could unplug the fridge for a few minutes just before 4 and see if that does it. Any other ways to test it?

That would be the best way.

That was it! Fridge defrost heater. It took a long time to figure it out. First, a windstorm came through and we lost power for four days. Then I could never get home or be awake when the thing went on. I also noticed that even on the days Sense did not detect the mystery heater it actually came on, Sense just missed it. Finally, just now the heater came on and I unplugged the fridge and watched the heater turn off immediately a full two minutes shy of when it would normally go off. Thanks for all the help. What geeky fun it is being an electronic device detective!

I think mine just found one, too - but at least the first time it found it, it lost track of it. I think it started following a television. I can see things better on my everything page. See below:

Here’s where it thinks it’s following it over about 15min:

Here’s what I think the device is actually doing:

That second picture looks a lot like the cooling unit in my fridge and chest freezer. The spike in the beginning in particular.

I think my fridge compressor was off at the time. It’s been detected pretty reliably and has a distinct profile :slight_smile: