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Electricity Usage Tripled After Installing Nest Thermostat?

Community Member

Installed a new Nest Thermostat, Model:GA01334-US, into a currently vacant property with a natural gas furnace (lennox) and with forced air.  No electric heat at the property.  Single zone heating and air conditioning.  Setup for the thermostat was fine.  Have the thermostat set in heat mode and locked at 60 deg F 24/7.  Home is in a northern winter climate and outside temperatures have been pretty consistent during the measurement period.  No one has been occupying the home during the measurement period - it is vacant and no other changes to electricity, appliances, etc. have been made.  As you'll see on the kWh chart, the home was averaging about 15 kWh of energy consumed per day up until the day the Nest Thermostat was installed - installed late evening on 12/27/22, 12/28/22 first full day of measurement.  Now its averaging about 3x that electricity use or 45 - 50 kWh per day.  The furnace is running 6-9 hours a day at 60 deg F (outside temps have been 10-30 F during this period).  The previous (dumb) thermostat was set to same temp - 60 F.  I'm at a total loss as to why the electrical demand would increase 3x fold after installing the nest Thermostat and literally no other changes in the home.  I've seen a few other posts about Nest increasing electricity use, but none seem to match my situation.  Any ideas?


Jump In Electricity After Nest InstallJump In Electricity After Nest Install

Nest Wiring DiagramNest Wiring DiagramFurnace Run Times Week 1Furnace Run Times Week 1Furnace Run Times Week 2Furnace Run Times Week 2