5 ms·

Of course it does. Heating up a hole in your ceiling does not efficiently warm the occupant. You want to introduce heat low and near occupants. Also, changing

by bluthru 12y ago

Of course it does. Heating up a hole in your ceiling does not efficiently warm the occupant. You want to introduce heat low and near occupants. Also, changing out multiple incandescents means more manufacturing, more truck deliveries to the store, more manufacturing, etc. vs. using a single LED bulb for two decades. If you live in coal country, then you definitely want to reduce your electrical load and instead rely on a less-bad option of natural gas for warmth.

lutorm 12y ago
Most heat from incandescents is infrared radiation, which travels. If you get useful light from the bulb, you also get useful heat. Plenty of rooms are heated with one big, honking radiator, which certainly is no more effective. That said, it's true that some of the heat ends up not being useful (just like a lot of the light from the bulb doesn't either) -- unless there's a heated story above, of course. And I never implied that I think it's a bad idea to get rid of incandescents, for all the other reasons you mention.
- bluthru 12y ago
  What's the attenuation of the UV from a light bulb in the ceiling?
  - ars 12y ago
    what UV?
    - bluthru 12y ago
      Wups, meant to write IR.
dredmorbius 12y ago
Manufacturing and shipping costs of incandescents are very small relative to their energy utilization, as reflected in costs. Your point about fixtures and heat losses through ceilings are actually well-taken. Recessed "can" lighting is actually a huge pathway for heat loss two ways: 1. The radiant heat from bulbs which is transferred into the ceiling and attic spaces, rather than the living space. 2. Other heat flow losses, including often very significant airflow, through the lighting fixtures. Thorsten Chlupp (mentioned elsewhere) includes lighting fixtures among his anti-penetration measures. He also keeps his wiring and plumbing runways along the inner insulates spaces, rather than outside the thermal barrier (with concomitant envelope penetrations).
WalterBright 12y ago
Two decades? My experience is LED bulbs last about a year.
- roel_v 12y ago
  The el cheapo ones, yes. There are expected lifetimes on LED bulbs ranging from 2000 (similar to incandescent) to 50000 hours. Of course the 50k ones are (much) more expensive.

by bluthru 12y ago

lutorm 12y ago

Most heat from incandescents is infrared radiation, which travels. If you get useful light from the bulb, you also get useful heat. Plenty of rooms are heated with one big, honking radiator, which certainly is no more effective. That said, it's true that some of the heat ends up not being useful (just like a lot of the light from the bulb doesn't either) -- unless there's a heated story above, of course. And I never implied that I think it's a bad idea to get rid of incandescents, for all the other reasons you mention.

bluthru 12y ago
What's the attenuation of the UV from a light bulb in the ceiling?
- ars 12y ago
  what UV?
  - bluthru 12y ago
    Wups, meant to write IR.

dredmorbius 12y ago

Manufacturing and shipping costs of incandescents are very small relative to their energy utilization, as reflected in costs. Your point about fixtures and heat losses through ceilings are actually well-taken. Recessed "can" lighting is actually a huge pathway for heat loss two ways: 1. The radiant heat from bulbs which is transferred into the ceiling and attic spaces, rather than the living space. 2. Other heat flow losses, including often very significant airflow, through the lighting fixtures. Thorsten Chlupp (mentioned elsewhere) includes lighting fixtures among his anti-penetration measures. He also keeps his wiring and plumbing runways along the inner insulates spaces, rather than outside the thermal barrier (with concomitant envelope penetrations).

WalterBright 12y ago

Two decades? My experience is LED bulbs last about a year.

roel_v 12y ago
The el cheapo ones, yes. There are expected lifetimes on LED bulbs ranging from 2000 (similar to incandescent) to 50000 hours. Of course the 50k ones are (much) more expensive.