Comment by pooper | Hacker News Reader

Comment by pooper | Hacker News Reader

Parent Full thread

> Resistive heat (like a light bulb or space heater) is terribly inefficient.

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.

I think heatpumps are something like 400% efficient for domestic heating, depending on outfoor temperature and so forth, so I guess resistive heating is inefficient by comparison, though I agree it seems weird to call close to 100% efficient "terribly inefficient". Probably losing heat from your lightbulbs to whatever is on the other side of your cieling is a significant factor too.

> I agree it seems weird to call close to 100% efficient "terribly inefficient"

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.

>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.

The second problem with LEDs is heat. LEDs produce a lot less heat than incandescents, but they also deal much worse with getting hot. Thus you need large (for surface area) and/or expensive (due to more expensive materials with high conductivity) heat sinks. Cheaper bulbs will tend to cheap out on this aspect, but there are also fundamental constraints especially in bulbs designed to fit traditional fittings.

And yet I've had two (name brand) LED bulbs die in the past year with <3 years of operational life. The drivers in most of these bulbs are garbage.

It's a shame that they can advertise the life of the diode itself with no regard for the rest of the electronics.

Reply on news.ycombinator.com