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Comment by oftenwrong | Hacker News Reader

It should be considered that LEDs are now being used for lighting in situations where there used to be no lighting at all [1]. The potential energy savings we could realise with LEDs may be negated by an increase in lighting itself. This would be an example of Jevons' paradox [2].

[1] http://www.lowtechmagazine.com/2008/10/led-light-cfl-b.html

[2] https://en.wikipedia.org/wiki/Jevons's_paradox

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> LEDs are now being used for lighting in situations where there used to be no lighting at all

While LED lights have certainly allowed for new applications, that article is nearly 10 years old and the future predicted has not come to pass. There has been no wave of LED-encrusted buildings. The roads don't glow. My bookshelves and whatnot don't either.

If LEDs deliver a 10x improvement in energy use, we'll have to use 10x as much light to offset the energy gains. How likely is that?

Have you been to Hong Kong or Beijing?

Lots of led encrusted buildings.

How many of those buildings had regular lights on them before?

Considering they are all relatively new construction, I doubt that any previous structures had them - this is a new, and awesome, phenomenon...

I freaking love what Asia is doing with their urban environments...

I just wish that the US developers would take note.

We are building the tallest building in SF ("salesforce" tower) and its a mundane peice of shit building. Literally zero aesthetic innovation.

True, but they're mostly decorative spots that hardly consume any light at all. Especially compared to old school flood lights that cast wide glows on sides of buildings.

>There has been no wave of LED-encrusted buildings.

Lol. Give them time. Here's two examples off the top of my head, in my city: http://urbantoronto.ca/news/2015/07/aura-illuminates-downtow...

http://canderelresidential.com/files/styles/building/public/...

I wish the trend was to reduce outdoor lights in cities instead of increasing them because it looks cool.

> My bookshelves and whatnot don't either.

Speak for yourself :)

I agree, though; I use a lot more lights around the house, but they're small and very directed for their purpose. Many of them are controlled by cheap, ubiquitous PIR modules so that they're only on when needed, with absurdly low quiescent current. I use less light overall because it's only where I need it to be, and I find this to be much nicer on my eyes, and generally pleasing for the evening. The added efficiency is just a bonus on top of all that. Many are undervolted, as well, so should last a very long time; the main concern is the lifespan and quality of the power supplies.

Got any recommendations for the LEDs, power sources, or PIRs?

> The roads don't glow.

There are those solar roadway people who are hoping to fix that. (I'm not optimistic, though. :) )

This is particularly true for increased outdoor night-lighting, which is harmful to wildlife: migrating birds, light-drawn insects and the bats that feed upon them, insects that require darkness to signal mates (fireflies), nocturnal prey-hunting animals, aquatic animals whose cycles are set to the lunar cycle -- as well as sleeping humans.

Most of the LED street lighting and whatnot I've seen has been more directed than what it replaced. Light pollution has improved, generally.

For a while the color temperature was terrible, but cheap and reliable warm phosphors have mostly fixed that.

As for private outdoor lighting, I'm not sure that less cost really affects that. People that made poor lighting choices (too much, too cool, too much spill) don't do it because it's suddenly cheap. They just paid more before. The answer to this is likely some degree of local regulation.

Same with heating. Heat pumps are increasingly popular in Norway since they will heat your house a lot cheaper than most of the alternatives. In reality people are increasing the temperature by 1-2 degrees Celsius instead of saving energy.

Read the same thing about four wheel drive cars, where the added safety is eaten up by drivers taking increased risks.

Interesting psychology.

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