There’s been a lot of speculation among those in the peanut gallery that the Cold House strategy was using more in space-heater electricity than it was saving in oil. My theoretical guesstimates said no, but since I wasn’t actually tracking my space-heater use, I admit to some trepidation in opening yesterday’s electric bill.
The news, though, was excellent. For December ’08, while the oil heat was off completely, I used an average of 13kWH/day of electricity. That is indeed a bit more than last December, when I used 11kWH/day. In absolute terms, the difference of 2kWH/day is equivalent to having just one space heater set on “HIGH” for a bit over an hour a day. Or having one 85W lightbulb on ’round the clock. In money terms, my bill was about $9.00 extra for the month.
That’s pretty amazing to me. It furthers my impression that the house has a certain “basal metabolic temperature” just from daily living, which is probably around 45F, and that very little extra energy was needed to keep the indoor temp at 52F/11C or so, which is what I’d become used to. Also, reclaiming some of the usually-wasted heat from electrical appliances (namely the dryer and the dishwasher) may have helped some.
But still, it’s a little too amazing. I did try to be mindful of how much electricity I was using for heat, but I can tell you with certainty that I used more than one space heater, one hour a day. Between the various strategies of space heaters, heating pad, electric blanket, hair dryer, and dehumidifier-heat-reclaimer experiements I would guess I used more like 4 or 5kWH extra per day. Which means that even while I was running these electricity-consuming items, somewhere I was also using less electricity than usual. Where?
The best candidate is the refrigerator. As I mentioned in a previous post, it almost never turned on while the house was cold. Web research suggests my fridge normally uses somewhere between 1.2 and 2.0kWH/day of electricity. I’d say that was down close to zero for the month of December, so that would offset a lot of extra heater use. I can’t think of many other appliances I used less while the house was cold, but maybe some things were running more efficiently. My laptop computer fan hardly ever came on, for example.
I went over to the website of the U.S. Energy Information Administration ) to see how my electric use compares with other peoples’, again fearful that I would now be using more than my share. But good news there, too: even my “extravagant” 13kWH/day for December is still 19% less than the average Maine household electricity use of 16kWH/day. And, the average Maine household’s electricity use is vastly lower than the average U.S. household, which is about 30kWH/day. In fact, these fascinating maps show that this state’s electricity usage is among the lowest in the country. Places like Texas and North Dakota use nearly three times as much per household. Colleagues across the border at Experiments In Efficiency report that the average Canadian household is even worse than the average U.S., using 33kWH/day.