More:“KENNETH HOMA, do you drive an EV?”

Let’s dig into the numbers…

Earlier this week, I posted that I had gotten two “alert” emails from BGE, my electric company.

The first email was a “NOTICE OF UNUSUAL ACTIVITY” …euphemistically asking  “what the hell is going on at your house?”

I reported that my son had charged his new Tesla overnight, and that probably triggered the alert.

The second email was more direct: “DO YOU OWN AN EV?” It showcased a chart that my energy efficiency had dropped from the borderline of “good” and “great” … all the way down to “fair”


Again, I pointed a finger at my son’s periodic Tesla charging.


Well, a couple of loyal readers politely challenged my inferences and doubted that EV-charging was the impetus for BGE’s email alerts.

So, I retrieved some numbers and did some back-of-the-envelop number crunching.

Let’s work through the numbers…


  • According to the U.S. Energy Information Administration: In 2020, the average annual electricity consumption for a U.S. residential utility customer was 10,715 kilowatthours (kWh).
  • Our home’s annual electricity consumption runs about 27,500 kWh …  which averages out to about 75 kWh per day.
  • When my son charges  at my house, it’s for about 8 hours, drawing about 40 kWh … about 5 kWh per hour of charging
  • So, based on an average day’s electricity consumption at my house, that’s a 50% spike in electricity consumed (40 /75 = 53%).


  • For reference, our biggest electrical draw is the HVAC that services our upper 2 levels (which get hottest in the summer and coldest in the winter)… with a smart thermostat that capture usage data.
  • Our upper level HVAC uses 5,300 kWh per year … about 20% of our total consumption … about 15 kwh on an average dayon hot days (high 80s and 90s) it spikes about 50% to 22 kWh
  • When BGE sees that spike, they know it’s a hot weather-related  event
  • When I got a 40 kWh Tesla charging spike on an average day, BGE red flagged me … since it was out of pattern … and sent the “unusual activity” alert.
  • When the spike happened a few times, BGE apparently concluded that I must have bought an EV which I’m charging from one of my home’s 110 circuits … and warned that I should brace for higher bills.

Bottom line: BGE drew reasonable analytical conclusions at the first spike … and after noticing a couple of spikes.

But, to answer their question : “No, I don’t drive an EV … I don’t own a EV … but, occasionally, an EV sleeps overs at my house.”


BGE’s question and my readers’ nudges really started me thinking about EVs.

For openers, I asked myself: “What if I did own an EV.  How much more electricity would I consume?”

That’s next up…

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