Blas,

Your question is a real can of worms .. as it involves the true biological nature of man, science and ecconomics.

Lumens are an obscurity .... the attached picture shows more than just the effect of lumens ... it shows the spectra of what we see and by the lamps with which we see it ..

LED's may never be the final answer .... and individual quality illumination may always be a price we just have to pay ...

As an older person, I have to say that visual light .. or the lack of it .. is very important to me .. and I have issues finding adequate light to see .. read .. and do all the things I once found just so easy .. one's eye sight changes as one gets older ... as does ones opinion to the question you have asked ...

Can I ask you to look at ....

https://www.youtube.com/watch?v=VIv4rdnnuf4

also,

http://www.physics.sjsu.edu/tomley/ObjectSpectra/tungstenbulb.html

http://www.soundandvision.com/content/led-vs-cfl-bulbs-color-temp-light-spectrum-and-more

and,

the man ... Dr. John Nash Ott

http://www.ottlite.com/t-full-spectrum-lighting.aspx

http://www.amazon.com/Health-Light-extraordinary-Affects-emotional/dp/0898040981

Title Health and Light: The Effects of Natural and Artificial Light on Man and Other Living Things

Author John Nash Ott

Edition illustrated, reprint

Publisher Devin-Adair Company, 1974

ISBN 0815957033, 9780815957034

Length 208 pages

It all adds up to a big ... and complex ... can of worms .. maybe with no final answer.

G

Blas,

Your question is a real can of worms .. as it involves the true biological nature of man, science and ecconomics.

Lumens are an obscurity .... the attached picture shows more than just the effect of lumens ... it shows the spectra of what we see and by the lamps with which we see it ..

LED's may never be the final answer .... and individual quality illumination may always be a price we just have to pay ...

As an older person, I have to say that visual light .. or the lack of it .. is very important to me .. and I have issues finding adequate light to see .. read .. and do all the things I once found just so easy .. one's eye sight changes as one gets older ... as does ones opinion to the question you have asked ...

Can I ask you to look at ....

https://www.youtube.com/watch?v=VIv4rdnnuf4

also,

http://www.physics.sjsu.edu/tomley/ObjectSpectra/tungstenbulb.html

http://www.soundandvision.com/content/led-vs-cfl-bulbs-color-temp-light-spectrum-and-more

and,

the man ... Dr. John Nash Ott

http://www.ottlite.com/t-full-spectrum-lighting.aspx

http://www.amazon.com/Health-Light-extraordinary-Affects-emotional/dp/0898040981

Title Health and Light: The Effects of Natural and Artificial Light on Man and Other Living Things

Author John Nash Ott

Edition illustrated, reprint

Publisher Devin-Adair Company, 1974

ISBN 0815957033, 9780815957034

Length 208 pages

It all adds up to a big ... and complex ... can of worms .. maybe with no final answer.

G

Since Gordon has already touched on the technology and light perception and quality, I'll comment on economics. The term you're looking for is Jevons Paradox, which is a subset of the Rebound Effect where an improvement in efficiency results in higher resource consumption. So searching for that in the context of lighting might be illuminating. :)

As far as the future of lighting goes, policy drivers will have an enormous effect -- whether through adjustment in electricity pricing or some awareness campaigns -- and these are a big unknown, and could vary from country to country.

Personally, I think the steady share of energy going towards illumination over the last century had a lot to do with the fact that over the last century we pretty much had two lighting technologies: the incandescent and fluorescent bulbs. The LEDs could be a game changer, but then again, the late Mr. Jevons might have something to say about that.

...And I stand corrected by this article:

http://www.sciencedirect.com/science/article/pii/S0301421508007428

(Steve Sorrell, "Jevons’ Paradox revisited: The evidence for backfire from improved energy efficiency", Energy Policy Volume 37, Issue 4, April 2009, Pages 1456–1469)

Lighting efficiency has improved considerably in the last century.

HI! Many thanks for Gordon and Pave, very illuminating answers and thanks also for the links, very instructive. Yes, the Jevons Paradox, I really believe there is a rebound effect, I don't know if enough to completely eliminate the effect of better efficiency, but at least for increasing energy consumption significantly. Like the price of goods, cheaper price would increase consumption.