Comparison

THURSDAY, DECEMBER 04, 2008

Some people have questioned whether using an electric space heater is actually better (more efficient, more economical, more saintly) than turning on my central heat. As a rough guide, I decided to compare the costs. Here are the results:

At current prices*, 1kWh** of actual heat in the house will cost 6.3¢ from oil (central heat), vs. 15.8¢ from electricity (space heater).

Obviously, heating the whole Palace with electricity would not be cost-effective. But so long as I am heating less than 40% (=6.3/15.8) of the house at any given moment, electricity becomes more economical. My kitchen “bunker” represents only 17% of the square footage of the house. My biggest bedroom represents 12%. My larger bathroom, 6%. So even if I had heaters going in all three places at once (35% of house) it would still be more efficient than turning on the furnace. So far, though, I’ve not had a heater going in more than one room at a time.

And, should oil prices return to their recent high point ($4.22/gallon, here) the balance point goes up to 80% of the house.

—————

* $2.14/gallon for oil, $0.15/kWh for electric. Calculation assumes 98% efficiency for electric heater (approximate) and 83% efficiency for oil furnace (latest measurement).

** For visualization purposes, 1kWh is approximately enough energy to heat a big kettle of soup from refrigerator temperature to not quite boiling.
POSTED BY TURBOGLACIER AT 9:43 AM
2 COMMENTS:

brushfiremedia said…
How much fuel is used to create 1kwh of electricity, I wonder.

12/4/08 7:03 PM
legallyblonde29 said…
What is the effect of leaving very cold rooms unheated next to warm rooms. The house is insulated only on the exterior walls. As a result, there is something less than 95% efficiency from the electric heat, I would guess, because some of the heat is lost to the unheated spaces nearby. Central heat would reduce this source of inefficiency. The alternative = insulating the interior walls or buying a much smaller house — more like the Vermont house you posted about a while back.

12/5/08 3:25 PM

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