Repeated short spikes - looks like an electricity comb

I’ve seen this over a few days, typically in the evening. Note the time scale … I can’t figure out what’s coming on, spiking for just a few seconds, and then off … lather, rinse, repeat.

I have a few other weird waveforms, but I’ll start with this one. Thanks to anyone who can help identify.

Do you have someone in the house with an electric heating pad/heating blanket? My sense shows a similar trend when my wife turns hers on…usually lasts 30-45 minutes until it times out (depending on brand…).

Let us know if that is the case - very interested in device profiles!


Yes, I also think that looks like some sort of small heating device. A fish tank water heater? Soldering iron? Hair Straightener? Keurig? Please report back when you find out what it is :slight_smile:

Could also be something like a wax melter.

My washing machine agitator motor gives me little spikes like that. Do you do laundry at night?
Edit: on closer inspection, my washing machine comb spikes are also followed immediately by larger valleys than what yours shows, I think the others are right, most likely something much smaller.

Hi! Thanks everyone for chiming in - you are a helpful group. She/we do have an electric blanket. As a test, I turned it on, and watched the graph. No real change. Disappointed, I went and did something else. I looked at it again ~20 min later, and I see the ‘comb’! It must’ve (?) took time to heat up, and this is the electricity draw to sustain the temp.


Yea looks almost like a coffee maker

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I found MOTHERS Keurig coffee maker was on 24X7. I poked around the menus and found the power saver option was disabled. Also found out my dad was roasting himself with an electric blanket at night. Parents are just under 90y/o and need a little supervision and a pair of warm pajamas.
I can watch the waveform and figure out pretty fast what is going on in the house. Not really impressed with the Sense AI thingy; but that is something that I am not interested in anyway.
BTW: I have a large built in refrigerator with 8 ea. 40 watt light bulbs. Everytime the door is opened; bamm 320 watts light and heat. LED’s installed and hardly a blip.


Agree, except I’m not making coffee in the evening, and that’s some of the time it’s on.

As noted in prior discussion, some coffee makers continue to draw power (ranging from about 1 watt to almost 60 watts) even when turned off. When this was raised, I decided to check my three Keurig models with my Kill-a-Watt meter. ALL THREE drew power when turned off, and the VUE model drew 57 watts.

So, if you have a Kill-a-Watt or similar meter, you can check yours. Smart plugs also work, but can be a pain to clear after you’ve contaminated their data this way. Otherwise, unplug your coffee maker(s) for a while and see if that helps identify this annoying trace.

Note also that lots of modern appliances draw power, whether or not they are turned on. TV’s are one common draw, but many other appliances do too. Some pulse as you describe, some just dray a small amount for their electronic controls. Our new “Instant Pot” draws a few watts continually, for example. So does one toaster oven.


If the standby/“off” wattage is in the 5w+ range you can also use Sense to do the check. Using the device Power Meter is not the way to do it, but you can see wattage changes in the mains Power Meter and/or in Settings>Signals.

If Sense sees the change, when you plug/unplug the device to make sure it’s really not drawing power, as “significant” the Mains Power Meter will show tags. This would best be done when your fridges, OLED TVs and other “noisy” devices aren’t on and your overall usage is low. A few cycles might be needed if the power draw (wattage) is low.

I call my random-data testing HS110 smart plug used for just this purpose “Tester”, but one could call it “Kill-a-Watt”. Maybe “Kill-a-Watt Pro”?

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I use both HS110’s and Kill-a-Watt to determine what’s drawing how much. Sure wish I had a 220v equivalent, because those are generally the BIG draws. I’ve had little success with Sense for such measurements, because my all-electric home has 176 (or more) devices and some of them are “noisy”. Sense has managed about a dozen in two years, and even those not particularly reliably.

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