Resistive heat (like a light bulb or space heater) is terribly inefficient. Resistive heat up high (in a ceiling or on a light) is even worse than resistive heat at ground level, because the heat escapes the dwelling without heating the occupants in the room much.
My personal concept of resistive heat is effective comes from a YouTube channel called Technology Connections. The argument is that almost all of the energy taken in by an electric resistive heater is given out as heat so it is pretty close to 100% efficiency. I understand that a heat pump is practically a better alternative for almost all use cases though.
Similarly, speaking of electric light bulbs, my understanding is there is no reason why an LED light bulb shouldn't last over ten years of continuous use. At least that is my impression from this reddit comment (please correct me if I am wrong)
https://old.reddit.com/r/HomeImprovement/comments/leunb1/why...
> There are many poorly manufactured LED lights out there. The LED itself is typically fine, but the driver electronics in the base tend to fail on poor quality products.
> I was having lots of failures for a while, but much less lately as I've tried to look for more brand name products.
A lot of my winter and nighttime electricity comes from natural gas.
50-60% of the heat energy in natural gas can get turned into electricity and make it to my house.
Then, it can be used to heat my ceiling a light bulb, where almost half of the heat immediately escapes my home. This is not a very good way to heat my house, versus my high-efficiency natural gas central air system that is more than 95% efficient in using the energy in natural gas to heat my home: it's about 3x worse.
Of course, even more efficient would be to use the natural gas to make electric power that runs a heat pump. That could be 200% efficient end-to-end.
Or, as the gas is already being pumped to your home, use the natural gas directly to power the expansion engine of the heat pump. Noisy, though.
Or use the gas for cooling in the same manner that a propane-powered refrigerator does. Although I have no idea how efficient that would be.
Resistive heat has efficiency ~1. That is better that almost any other heating source with exception of heat pumps and cogeneration. If we consider visible light as a separate gain, then light bulb has efficiency ~1.02
> Resistive heat up high (in a ceiling or on a light) is even worse than resistive heat at ground level, because the heat escapes the dwelling without heating the occupants in the room much.
For light bulb, i guess most energy is dissipated by IR radiation and only small part by convection. So it heats whole room and occupants, but not air.
... if you don't charge generation and transmission inefficiencies against it. High efficiency natural gas heating systems are 98% efficient; compare to natural gas combined cycle plants that are ~60% efficient, plus a few percent more lost to transmission and distribution.
> with exception of heat pumps
Sure, that's the actually-efficient source of heat from electricity.
> For light bulb, i guess most energy is dissipated by IR radiation and only small part by convection.
For incandescent bulbs, this is unrealistic. The bulb is quite hot and heats the air around it and the fixture.
Moreover, of the IR, a whole lot also strikes the fixture and is conducted into the ceiling.
Well yes. Statement 'efficiency of X' generally means 'useful work of X / relevant energy input into X on X boundary', not including efficiency of whole supply chain from primary energy source.
It does if you only consider the efficiency of the electricity -> heat conversion, but electricity generation itself is often not that efficient. It can be a lot more efficient to go fuel -> heat than fuel -> electricity -> heat.