Heat1 came on in the summer

[ixu]

You’ve got similar happenings to what is discussed in this thread:

Sense has detected my air handler, but only sorta but not really. Does an air handler do anything besides blow air?

Pure conjecture here but it wouldn’t surprise me if that spike is actually a defrost cycle on a fridge/freezer (which invariably happens once every 12/24 hours) whereas the nice Device waveform that Sense presented you with was a phantom triggering of an actual load. Meaning: some other device signature or power pattern looks like the defrost cycle to Sense. That said, an actual defrost cycle (if not malfunctioning or triggered repeatedly by a wonky thermostat) usually runs for 10+ minutes to d…

It looks like a “wait-and-see” situation to me.