Letters to the Editor
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All wasted energy is converted to heat
First off, I'm not saying it's a good idea to keep incandescent bulbs. A clear problem occurs in warm weather when you don't need any extra heat and may even be running an air conditioner to remove the heat from the inefficient light sources.
But in the winter, there is no obvious way to improve efficiency by switching between electric heat sources. Electric heat is inefficient already because so much of the source energy was wasted in generation and transmission. But by the time it gets to your house and runs through a heat pump, heating coil, or light bulb filament, the energy consumed by the device will eventually be dissipated as heat in your house. So any inefficiencies in your light source--difference between input power and output light--is converted to heat. Even the light is going to be converted to heat rapidly when it is absorbed by an opaque medium.
The only efficiency argument for a space heater is that you can direct the heat exactly where you need it. This has some validity. For instance, your ceiling light bulbs are going to heat the air above your head and much of that will rise out through your roof (depending on how well insulated it is). I'm not sure how an electric heat pump improves matters, but I'd have to do some research.
The issue with incandescent bulbs is not that they are inefficient heat sources. All electric appliances are equally efficient converters of input electricity to output heat. The main issue is your control over where they put that heat.
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@paulBC
"I'm not sure how an electric heat pump improves matters, but I'd have to do some research."
There's a big difference between "electric heat" and an electric heat pump.
With "electric heat" (more properly "resistance electric heat", the electric energy is passed through a resistor, where it becomes heat. Same as in an electric stove, coffee pot, water heater, etc. One unit of electricity gives one unit of heat.
But in an electric heat pump, heat is extracted from something (say, the ground) and transferred to where it is needed (heating the house). The source gets colder, of course, but if it's big enough and warm enough that's not a problem. A heat pump system can transfer several units of heat for each unit of electricity.
First-generation heat pumps were "air source" - they used outside air as the heat source. This is simple and inexpensive to build, but when the air outside gets really cold it doesn't work well, and below a certain temperature doesn't work at all. Newer-generation system use the earth, ground water, and other sources of heat, rather than the air. Some forms of "geothermal" heat work this way.
The main reason you don't see more newer-generation heat pump systems is that they cost more to install. But as energy prices rise, the payback interval shortens, and you'll see more of them.