New device called Light 1 comes on hourly

I’ve had Sense installed for 6 days and yesterday it found a device that comes on regularly at 52 minutes past the hour. It shuts off after 5 to 10seconds. It is consistent. Sense recognized it as a light. It measuring 100w. As I write this it just came on at 8:51 and off in 5s. Again at 8:53 and off 10s.

Sense likely thinks it’s a single 100W incandescent light. If you don’t have any incandescent lights then it’s probably something else and not a light. Something with a resistive load. Off the top of my head, the only type of thing I can immediately think of is something like an electric kettle keeping water warm. But the duration seems to short for that.

Try turning your ice maker off and see if you still see it turn on.

Outdoor security/motion lights?

Motion detector lights wouldn’t be running during the day, and definitely not at the same time.

I suspect an appliance with a timer, and in particular a modern refrigerator…they have several small heaters and some are highly computerized.


I turned the breaker for fridge off and light came on right on time. I’ve eliminated the stove, microwave, and laser printer as well. My setup has solar installed remotely from panel sense is in.

Heat tape controller? Maybe it comes on hourly to see if it is needed, then quickly determines it is not.

Can you share the Power Meter waveform for it? Sometimes there are hints in that if it is not a purely square-looking resistive load.

100 W for that short of a duration doesn’t sound like a heating element, especially with the consistent timing. Being hourly makes me think it is a component of some device with electronics.

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If you watch the Sense Labs - Floating Neutral tab you can see the power on each phase of the line in real time. Watch it when you expect the mystery device to appear and you should be able to see which leg the load is on. That will cut out half the possibilities.

You can see it’s drawing 100w and it was on for 18 minutes at 7:52 mark. That’s a first.

Do they all have the little spike at the beginning? That looks similar to a condensate pump, like you’d have for a AC or dehumidifier condenser. It’s in the right wattage range, too, and could be consistent if your AC or dehumidifier is running at the same rate.

18 minutes is odd, but it might’ve missed the off event.

FWIW, my condensate pump uses 82w and runs for just a couple seconds, but VERY often, especially when the AC is on, and not regularly. Here are my waveforms.