What could Heat 3 be?

It is almost 900 watts very regularly, it takes a break from 12 PM to 3 PM.
I cannot imagine what it could be.

This is a good place to start:

128x, 198m ==> on for about 1.5 min ==> thermostatically timed device like a heater targeting a certain temperature … this would comport with, say, an electric in-floor heater that gets the sun shinning on it midday while meanwhile the house is warmer due to solar gain. Many options. Read the help articles and methodically narrow things down.

Does the usage coincide with when someone is home?

We are back from vacation and both getting over jet lag so no one has left the house since I started monitoring.

Thanks for your time in helping with this.
It is absolutely not a heater of the type you are mentioning.
I have three space heaters and two have been ID’d while number three isn’t showing up when powered on yet.
Also, it comes on after exactly 20 minutes. Not one minute longer or shorter and stays on for the same 90 seconds or so.
Not the type of pattern a heating device would exhibit, for example it was super cold on day one and moderated for the second.
There is absolutely nothing that I can pin down as even a possibility.
I thought maybe a crazy active fridge defrost, we have a new Samsung fridge, the old one had horrible ice maker build up, maybe they went crazy with the new defrost cycle. I guess I can try unplugging it for an hour and see if that goes away.

Very perplexing.

Nope, unplugged the fridge and it came on 20 minutes later again.

Maybe some closeups of the signatures would help but to me it looks more like an interpolated “component” (possibly of a component) rather than the complete signature of a device.

I would trust that it’s a heat/resistive component of some form. A space heater has a well defined wattage at different settings (which may “step” with multiple elements) so you could potentially rule those in or out.

Jetlag … so …

Left an iron on? Hot plate?

I know you’ve ruled out the fridge but using an HS110 smart plug (on a fridge or other complex signature) can really help narrow down mystery house components.

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It has to be something on a timer (not set by me) that says every 20-22 minutes come on for 90 seconds.
I did suspect my electric vehicle, it was plugged, seems plausible to wake up every 20 minutes and check to see if it is charged.
Well that isn’t it.
I have a KillAWatt device that I plugged into the deep freezer in the basement and it shows 0 watts when the last Heat 3 alert went out.
It makes no sense, see what I did there?

No to hot plates, irons, etc. Plus, why would they take a break midday?

Any instant hot - hot water heaters that are on a timer ?? I have one that comes on for 2 minutes every hour or so at 780W.

Nothing is on a timer except for three space heaters, all ruled out or accounted for. Nothing.
Very frustrating. Water softener runs at night and no way uses 900 watts.
It mimics something like a runaway defrost cycle but as I said, both fridges have been unplugged at it’s expected 90 second fire up and it still happens.
Standard hot water heater tank. I did take it offline just to check, wasn’t it.

How about a coffee maker or espresso machine?
Or ice dam tape? Heated pipe tape?

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First of all I really appreciate the help!
I will find it eventually, I was just hoping for someone to come up with an idea to narrow the hunt down.
I have a coffee pot but it doesn’t have a heated base, it is one of those insulated pots.
I have turned off breakers and narrowed it down to about 4. Currently they are off and I haven’t had it spike in 50 minutes.
Every 20 minutes I am turning one on.
My wife has those scented plug ins all over the house, hard to imagine one of those is rogue and drawing 800 watts. Seems like it would melt.
I will report back!

Could a UPS spike like that every 20 minutes? I have a few of those.

Plug-in scent diffusers are somewhere between 2.7W and 4W continuous - no spikes. A UPS is an interesting theory. Do you have line interactive or double conversions UPSes ? I have a couple of line interactive UPSes but have never measured the inbound power with a smart plug. Wondering if a line interactive model would start sucking power like that in bursts if it couldn’t keep the UPC battery at the requisite level of charge. That pulse averages out to 66W continuous, except for the the mysterious quiet hours… You might want to get an HS110 and use it as an “explorer” on the inputs of the UPCs.

It would be fruitful at this point, I think, if you post an image of the Mains Power Meter … at a day scale and zoomed in around the 900w cycles (not tooo close).

My suspicion based on what you’ve told us already is that it could well be an “artifact” of something larger or indeed a concurrent usage of multiple devices.

OK, found it, crazy find.
Sense saved me a few dollars right off the bat.
I have a whole house fan. There is a two speed switch in the landing below it.
In the winter I throw insulation on top of it and I have a on/off switch in the attic to toggle to off so that if someone hits the switch in the hall it won’t come on. But it only shuts off one leg.
The switch in the house was in the high speed position.
So I am guessing the capacitor was fully charging in those 90 seconds and 20 minutes later it would try again.
Maybe I am way off here but regardless, the phantom heat 3 is no more.
I would have figured it out in summer I guess, but it was costing me $8.50 per month during the winter months.


Should I delete the Heat 3? Seems like when I use the fan in the summer it will have a different signature.

Deleting it won’t cause any problems … but you could also keep and rename it for reference.

And if you account for the likely cold-air sucking action in Winter you may well be looking at more savings than that. Well caught.

You may want to post this to SenseSaves.