Hacker News Reader

Comment by Fordec | Hacker News Reader

Short answer, yes.

Long answer, you'll need to really jack up the power consumption. Replicating a thing that in itself an energy source needs waaaay more than just a 60W light bulb.

View on HN

60W would be some 10 LED lights that each are 100W equivalents to old glow lights. That would probably already do the trick in a small room.

Do people really still use old “light bulbs”?

> 60W would be some 10 LED lights that each are 100W equivalents to old glow lights. That would probably already do the trick in a small room.

Not really, daylight is not 10 times but much more brighter than a 100w incandescent lamp, such illumination (e.g. it has certain uses to help seasonal depression) exists but it's very bright compared to normal indoors lighting.

The old 100w lamps were ~1600 lumens; outdoors daylight is something like 10k lumens/square meter in shade (direct sunlight would be another order of magnitude more), and an appropriate number for the surfaces of a small room would be in the ballpark of 100 of such LEDs so 600w of electricity.

Interesting! Thanks for the correction.

Yes, I do. Where I live, winters are long, so none of the heat is wasted. But that aside, the real reason is the quality of the light. Spectra! Incandescent lighting is a black body radiator basically, so you will have a full spectra curve even if it is weighted toward the red side. The downside of LEDs (and the CCFLs that preceded them) is that they only have a few narrow peaks in the spectra, R G B at differing heights and the rest of it is low. This is why colour rendition generally looks poor, and even worse, they flicker! Because we live in a society that wants everything as cheap as possible, the LEDs generally flicker at 60 or 120 Hz, sometimes higher. This causes a strobing effect, etc. This can be avoided by using DC current, but who uses that? CCFLs used electronic ballasts with much higher rates but they're not on the market anymore. Incandescents have a small degree of flicker too, but it's basically non-existent because as black-body radiators they continue glowing until the next pulse arrives.. LEDs are not like that, they are instant on-off, and their "dimming" trick is usually pulse-width-modulation where they're still fully light, but their duty cycle is spaced further apart, you think it is dimmer but it is not.

LEDs are a terrible technology for lighting.

Reply on news.ycombinator.com