Figuring out Heat 5

This device was only detected about a week ago, but Sense has data going back to around the beginning of Oct. It seems to come on roughly every 24 - 30 hours (meaning it runs almost every day but occasionally skips a day), consumes just under 500W, and runs for almost 10 minutes. Here’s a bunch of screenshots.


Here is the power meter for device 5 when it ran last night just before 5am.

Here is the full power meter for the same time period.

I noticed the spike at the beginning that didn’t show in the device specific power meter, which could indicate a motor of some kind, but I wasn’t convinced they were related. So I started looking at my other devices to see what else ran at that time. Turns out my chest freezer did. Here’s the power meter for it.

So I wanted to see if there is a correlation between the two. (hint: I don’t believe there is).

Here is a power meter graph of heat 5 on 12/15.

Here is the chest freezer during the same time period. No overlap.

Just in case, I checked another time. Here is heat 5 on 12/14.

And here is the chest freezer for the same time period. There is a bit of overlap at the end, but not at the beginning where the power spike is.

To head off some questions: I do not have a coffee maker of any kind whatsoever. The chest freezer does not have an auto-defrost. I have to manually defrost it every 6 months or so.

My personal theory is that this could be the auto-defrost of my normal freezer. But I don’t really know a way to test that. But I don’t have anything else that I can think of that would be a resistive heating element that comes on without user input other than my water heater, and I know it can’t be that.

Oh yeah, and here are the community suggested names.

Looks like a refrigerator auto-defrost cycle to me. Mine runs about 488w at about the same time-cycle as yours.


I agree, almost surely a defrost element. Ways to verify:

  • Correlate your graphs where it doesn’t come on with fridge/freezer usage … was the fridge/freezer not opened for those periods? (Remember also that Sense doesn’t necessarily catch the defrost element every time it activates – perhaps for those periods there was something else running that clouded Sense’s view)

  • Check the specs on your fridges/freezers.

  • Put a smartplug on the fridge/freezer.