Another Sense success story:
Background
I live in NW FL and yesterday we used heat for the first time since February. We have upstairs and downstairs electric heat pump systems, both with secondary 10kW electric aux heating coils that are supposed to engage if the heat pump can’t handle the load quick enough. Without the aux heat, the heat pumps use about 2.8kW. Thus about 12.8kW when the aux heat is engaged. The heat pumps work very well without aux heat and we rarely need it. Most years aux heat never comes on.
Discovery
Sense warned me that we had a spike about double the highest level seen since I installed it this summer. Turns out the upstairs heat pump system was turning on the aux heat whenever the heat cycled even though it wasn’t needed (only 1 degree room temp corrections). I looked up the thermostat data and it turned out to be a model that is incompatible with secondary (aux heat) systems. An AC repairman changed out the thermostat over a year ago (!) during a repair and it seemed to work fine.
Correction
A trip to Home Depot for a proper thermostat fixed it. See attached - similar outside morning temp’s, but a huge reduction in power usage.