Comment by parametrek | Hacker News Reader

Comment by parametrek | Hacker News Reader

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> The energy efficiency of LEDs still doesn't beat CFL, except for really really expensive LEDs.

Not at all!

CFLs cost $1.74 per bulb with an efficacy of 64 lumens/watt [1]. LEDs cost $12.47 per bulb with an efficacy of 84 lumens/watt [2].

As far as LED bulbs go, $10-$15 per bulb is a pretty typical price. A more correct phase is "The average LED is 30% more efficient than a CFL, but costs 7x more." Anyway, both halves of your statement are wrong.

The big savings comes in flexability. LED bulbs are easily dimmable. Dimmable CFL bulbs are expensive and don't work well. LEDs can be turned off and on quickly without wearing them out. I go through a lot of CFLs in my basement, because the lights are turned on for three minutes at a time, several times a day. They actually burn out faster than the incandscents! Though in most cases it does not make sense to replace CFLs with LEDs yet.

Eventually it will, see Haizt's Law [3]. CFL tech has been improving too but not as fast. In 1980 florescent tech was at 34 lum/watt. Doubling every 30 years is a dead end.

[1] http://www.homedepot.com/p/t/100687000

[2] http://www.homedepot.com/p/t/204084366

[3] http://en.wikipedia.org/wiki/Haitz%27s_law

First, a arithmetic error: it's $0.74 per CFL, not $1.74. So so the LED costs 17x as much as the CFL.

Congratulations: You found an example of a really really expensive LED - which is exactly what I said.

And I've seen this LED before - it's the very first one I've ever seen that beats a CFL for efficiency, and it does it by having a CRI of 80 (the legal minimum). So the color advantage LEDs have over CFL? Not for this bulb - this bulb looks terrible, so bad that it's going to turn people off from LEDs, the same way the early bad CFLs made people think they are all bad.

How exactly are you saving anything from flexibility? Who cares if they are dimmable, the majority of the time you don't, and the tiny savings in electricity when you do hardly matter.

I turn my CFLs on and off quite often and I go years between having to replace them. And they cost 74 cents - replacing them is hardly an expensive proposition even when they fail (which they usually don't).

Check the efficiency of LEDs that cost no more than $5 (still 6x the price of a CFL, but reasonable) for around 800 lumens, if you find one that beats - or even matches - a CFL let me know. And make sure the CRI is comparable too. A low CRI CFL is also much more efficient.

Haizt's Law has nothing to do with efficiency. Also, the theoretical max for efficiency is 250 lm/w. It's going to get much much harder to improve things as we get closer.

I agree that eventually LEDs will beat other technology. It's just not there yet.

> First, a arithmetic error: it's $0.74 per CFL, not $1.74. So so the LED costs 17x as much as the CFL.

Sorry, what? The linked four pack of CFLs costs $6.97. You must have been doing some very interesting taxes this week if you think 6.97 / 4 = 0.74. (Apologies if you are not American.)

> Check the efficiency of [800 lumen] LEDs that cost no more than $5

They don't exist. Even cheap direct-from-China LED bulbs* are more expensive than that. $10-$15 per bulb is the typical cost and you'll be hard pressed to find 800 lumen (60 watt equivalents) for any less. I'll gladly check their efficiency if you can show me where to get that many lumens for that price.

* Actual lumens. Many Chinese reseller sites will outright lie and you need to check the manufacture's website. Eg, http://dx.com/p/193927 says 1008 lumens while http://www.sencart.net/e27-24smd-5060-led-pure-white-lights-... says 700 lumens.

> The linked four pack of CFLs costs $6.97.

That is very very interesting, for me the price is listed as $2.97. I can post a screenshot if you like.

I'm wondering if it might be because there are utility rebates in my area, and my local store has a lower price.

> They don't exist.

I figured. I don't think the time for LED replacement bulbs has come yet, but we're getting there.

Although I am considering this fixture http://www.ebay.com/itm/170922117326 for a new installation because once I include the costs of the hardware the price is a wash, and LEDs are much better for outdoor use.

I do hope they are not lying about the lumens though.

I think LED specific fixtures are going to be a much better choice for now, rather than edison base bulbs.

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