FEB 14

Incandescent light bulbs are really little space heaters with a side benefit of producing some light. They are an old technology that is being phased out for many applications by more efficient alternatives. Now, in addition to the LEDs and CFLs, we can add ESL bulbs, which have started to reach the market, to the available technologies.

We've been watching for Electron Stimulated Luminescence (ESL) lighting technology for a few years. It is now commercially available with the introduction of the Vu1 bulb. ESL lighting uses an electron gun to stimulate a phosphor coated surface for illumination, much like an old CRT or television tube. The bulb is actually a vacuum, with no mercury (or anything else) inside it, so disposal and recycling is easier.

The Vu1 bulb has an expected lifespan of 11,000 hours, which can be 5 times that of an incandescent and close to that of a good CFL. It uses 19.5 watts to produce 500 lumens, so it falls in between CFL and incandescent in efficacy. The color-rendering index (CRI) of the ESL bulb is 90+, again falling between an average CFL with a CRI of 80 and an incandescent with a CRI of 100.

Street pricing for the Vu1 is about $15*. That’s more expensive than a CFL these days, but that’s in the range of what CFLs were a decade ago, and LEDs with this color quality aren't at this price level, either. For further information and a more subjective review of the light, you can read a longer review about the Vu1 light on my personal blog.

[Disclaimer: Vu1 provided the sample bulb to me at no charge for my review.]

[* Edited to add: After posting this yesterday, I got a call from William Smith, the chairman of Vu1. One thing he wanted to emphasize is that the company expects the price for this bulb to be less than $10 within 18 months, as production ramps up which is in the range of other dimmable bulbs.]

Comments (13)

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written by Mike Okrent, February 15, 2012

I just bought several LED lamps for $11 each at Lowes. They are warm color temperature with 7.5w. What makes the ESL at $15 better?

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Radiation?
written by Foraker, February 15, 2012

Does the ESL bulb emit (low level) radiation like the old CRT television screens?

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With Mike!
written by Jeff, February 17, 2012

Mike,

I've gotten those same bulbs all over my house! I have been slowly upgrading and I love them! I bought them when lowes had them on special for $9 a piece. I don't see how a technology like this can compete when LED's will last much longer than CFL's and they use less energy as well. I will have to wait for something brighter and more efficient than LED's not something that is in between Incandescent and CFL's.

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Preorder
written by Brian, February 19, 2012

I purchased these about 8 months ago as a preorder directly from the manufacturer. I have had a few fail, which they are replacing, but I do have to say that I really enjoy the quality of the light. They are fully dimmable (which many LED's are not) and they produce a much higher visible spectrum vs LED's. As a reply to Mike above, LEDs produce a very narrow range of color in a specific area of the spectrum. They may look nice and warm, but can get very hard on the eyes over prolonged exposure.

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written by rocklee, February 23, 2012

Just as what Mike Okrent asked ,what's the advantage of ESL light bulb than CFL bulbs and LED bulbs ?
Can ESL bulbs be manufactured in lower cost ,or ESL bulbs can be used more widely ?

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100w
written by bill s, February 28, 2012

What is there to compete with a regular 100 or 150w bulb? All I see are replacements for 60w bulbs. My eyes are not good - I need more light!

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written by Markov, February 28, 2012

To review:
The Vu1 bulb has an expected lifespan ... close to that of a good CFL. It is less efficient than a CFL. The Color Rendering Index is superior to a CFL. And it is more expensive than a CFL.
... so it comes down to the fact that it is cleaner to recycle and is newly available. Am I missing something?

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none
written by Allen McKenas, February 29, 2012

This bulb stimulates a phosphor with an election beam. What about induction bulbs, which stimulate a phosphor with RF energy. They last 100,000 hours and are more efficient than CFLs. They currently are bulky and used for streetlights or commercial spaces. I'm sure they could be made smaller and cheaper. I use two of them in my garage and just bought a streetlight for yse as a yard light.

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Mr
written by N T Nair, February 29, 2012

Everyone is waiting for the refined LEDs to use as the ultimate lighting solution, when its prices come down. That doesn't mean that other ecofriendly alternatives need not be searched for. ESL could be a sure alternative to atleast CFLs. Let there be more manufacturers of ESL.
What are the induction bulbs? Are they available cost effectively?

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I'm still waiting for the alien technology to land on this planet any day now
written by Paul Streicher, February 29, 2012

Something that will beat out all others at the moment that will offer any spectrum of light at any brightness and be cheaper retail than anything we have now. I know it will happen, but when is the question.

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Increasing color spectrum with LED lights
written by Martin, March 03, 2012

If you want a wider color spectrum using LED downlights, then you could use 8 downlights configured as 4 warm (2800K) and 4 Netrual (3000K) as an example. If these are wide angle lamps then you would get a mix of color spectrum, which can be more pleasant. I think also LED chips are available which produce a much wider color spectrum, such as daylight.

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written by flight training, March 05, 2012

I think this things are awesome

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written by Jan Stephens, March 07, 2012

While it is for sure desirable that new lighting technologies get developed, the classic LED has still some advantages over the ESL.

20 Watt for 500 Lumen converts to a luminous efficiency of 25 lm/w (Lumen per Watt), which is not really competitive to current LED lights. They have values around 50-100 lm/w and higher meaning that they emit at least the double amount of visible light with the same electricity consumption.

In addition to that, if you consider the higher lifespan of LEDs (around 50.000 hours), the lower price of ESL lights isn't so competitive.

Just to things to keep in mind. I didn't test these, so there may be other advantages.

However, it's still way better than compact fluorescence with their mercury or even incandescent light bulbs!

Do these lamps ship with different color temperatures?

If somebody is interested, I started a little experiment where I try to simulate different color temperatures of lights with a 3D software using an unbiased renderengine at my blog.

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