I always thought that heating with electricity was supposed to be a bad idea. Yes, electric resistance heaters—which operate like the element on an electric stove—are pretty efficient at turning electricity into heat. But turning fossil fuels into electricity is incredibly inefficient. In a typical coal-fired power plant, only about a third of the energy content of coal is actually turned into electricity; the rest is wasted. The newest types of gas-fired power plants are more efficient, but still waste about 45 percent of the energy content of the natural gas they burn. Then, transmitting electricity to your home wastes additional energy.
So all things considered, it makes far more environmental sense to heat your home with gas directly than it does to burn the gas to produce electricity, transport the electricity to your home, and then use it to power a baseboard electric heater.
But electric-powered heat pumps—which work sort of like refrigerators in reverse—are making me change my thinking about using electricity for home heating. Unlike resistance heaters, heat pumps don’t actually convert electricity into heat. Instead, they move heat from place to place, which is much more efficient: one kilowatt-hour of electricity in a heat pump may produce two to three kilowatt-hours of usable heat. (And no, this doesn’t actually defy the laws of physics: heat isn’t being created, it’s just being moved around.)
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The Northwest Power and Conservation Council has identified heat pumps as the second most-important source of electricity savings in people’s homes (see page six, here–but be careful, it’s a big .pdf download). And as this Canadian report confirms, heat pumps beat just about every other heating method in terms of the amount of greenhouse gases produced per unit of heat generated—even in British Columbia, where virtually all of the electricity comes from hydropower. And unlike gas-fired furnaces, heat pumps can be completely greenhouse-gas neutral, provided that they’re powered with electricity that wasn’t generated from fossil fuels. Even the new generation of high-efficiency gas furnaces can’t make that claim.