I'd imagine on the whole it's wasted. Half the year they aren't just generating wasted heat, they're increasing cooling costs. The half of year that the heat is wanted, it's usually above you, and I imagine that heat is being generated less efficiently than a purpose-built device.
> that heat is being generated less efficiently than a purpose-built device.
“efficiency” is meaningless when heat is desired. if you pump 100W into a device, and it “wastes” all that power, you have successfully generated 100W of heat. only heat pumps can be more efficient.
Exactly. And if you have a whole house/apartment electric heating system it is very likely that it is in fact heat pump based. So you are better off using that for heat than the lights.
If your whole house/apartment heating system is gas or oil based, that will probably be even cheaper than the heat pump electric version.
>if you have a whole house/apartment electric heating system it is very likely that it is in fact heat pump based
Hmm, where? I have never knowingly been in a house with a heat pump in the UK, and lots of cheaper flats have electric radiators and immersion heaters.
Not quite – some energy was lost converting from its source form to electricity. If you heat your house by directly burning natural gas (the most common way in cool countries like the UK) then it can still have an efficiency advantage over converting electricity to heat.
This is true but - especially if your house is not well insulated - getting heat in the right place matters too - most people don't need to heat their roofs or ceiling spaces. There's also a more minor point on time of day you want heat or not.
The only thing that can be more efficient is one of the most common forms of heating devices.
During the summer, it's also extra inefficient to pump 100W into a device producing heat and then pump even more power somewhere else to cool down the room.
I had a friend with a condo in Chicago with a 400-500 dollar a/c bill plus another 200-300 year round bill because the builders hated the earth and universally used halogen bulbs. But on the plus side the heating bill was probably 50 bucks for the year.
Heat pumps have higher than 100% efficiency because they extract heat out of air / water. 100% is a very low efficiency for electric heating. Anything lower than 400% is considered below average.
