LED vs. CFL - Make sense of this...

[JHZR2]

Was looking at some LED and CFL floods at HD. Actually bought one of each to test at home.

HUH??!?

They are both 1300 lumens, but one is a 90W equivalent while the other is a 125W equivalent? What gives?

Also, I thought LED was more efficient... Here it shows the LED takes 24W for 1300 lumens while the CFL takes 23. Is this because the dimmable LED has less efficient electronics inside to make it dimmable?

That LED bulb is heavy. Lots of metal around the light source. Id imagine that will help with life of the electronics?

 

[OVERKILL]

What was the price difference between the two? Country of origin?

 

[daves87rs]

Maybe the LED will be brighter? Thinking out loud here...

 

[JHZR2]

Originally Posted By: OVERK1LL
What was the price difference between the two? Country of origin?

LOL, its horrid...

CFLs are two for $10, the LED was $40!

No lights besides a few specialty bulbs and maybe some incandescents are US made. Really sad! Know of a source?

The good thing is that HD has a nice loose return policy, so Ill check them out and then send at least one of them back...

Is there such thing as a first world LED or CFL? Perhaps Japan?

 

[JHZR2]

Originally Posted By: daves87rs
Maybe the LED will be brighter? Thinking out loud here...


Wouldnt the lumen rating then be higher??? Maybe it is the total radiance, which to some extent isnt worth much and goes back to the efficiency point (photons in terms of IR or any other non-visible light dont do much for me).

From wiki:
Quote:
The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the total "amount" of visible light emitted by a source. Luminous flux differs from power (radiant flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light, while radiant flux measurements indicate the total power of all light emitted, independent of the eye's ability to perceive it.

 

[Sunnyinhollister]

Originally Posted By: JHZR2
Originally Posted By: OVERK1LL
What was the price difference between the two? Country of origin?

Is there such thing as a first world LED or CFL? Perhaps Japan?


Cree and Philips have LED plants in the US. Philips assembles the final product in the far east. I'm not sure about Cree.

 

[JHZR2]

Originally Posted By: Sunnyinhollister
Originally Posted By: JHZR2
Originally Posted By: OVERK1LL
What was the price difference between the two? Country of origin?

Is there such thing as a first world LED or CFL? Perhaps Japan?


Cree and Philips have LED plants in the US. Philips assembles the final product in the far east. I'm not sure about Cree.


Great. Some sources to chase!

 

[daves87rs]

Originally Posted By: JHZR2
Originally Posted By: daves87rs
Maybe the LED will be brighter? Thinking out loud here...


Wouldnt the lumen rating then be higher??? Maybe it is the total radiance, which to some extent isnt worth much and goes back to the efficiency point (photons in terms of IR or any other non-visible light dont do much for me).

From wiki:
Quote:
The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the total "amount" of visible light emitted by a source. Luminous flux differs from power (radiant flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light, while radiant flux measurements indicate the total power of all light emitted, independent of the eye's ability to perceive it.


Always thought that LED were brighter overall. As crazy as it sounds, they seem kinda hard to compare. I have an led floodlight in my basement (smaller one), and it seems like the Led offers a bighter white light than the cfls..just what I've noticed...

Mind you it seems like it in my case..

 

[Cutehumor]

LEDs look good to me and sound awesome. the price is too high at the moment.

 

[si1491]

I also have noticed that LED lights tend to have quite a sturdy frame/structure due to the amount of metal used. This makes them very heavy but I wonder if it is more of a heat sink (due to some of the shapes I have seen) rather than a just sturdy and long-weathered design. Are lighting fixtures they will be used in designed sturdy enough to support that heavy thing for the life of the bulb?

 

[tgferg67]

The "equivilant" is probably a measurment of the directional light you will receive in this application. Lumens is an omnidirectional measurment and LED's are a more directional light source. In directional or downlight applications LED's seem more efficient per watt than fluoroescent. In a typical bulb/fixture where the light is coming from all around, lumens would be a more accurate measurement for comparison.

 

[bmwjohn]

just a guess, but different bulbs have different lumens, in the sense that a clear, cool white incandescent might be rated as 1000 lumens and 100 watts, whereas a warm white frosted bulb may be 100 watts and 800 lumens. So, they are NOT comparing identical specs, in real life.just a thought.

 

[JHZR2]

I do have to say that I like the light coming from the LED. Its just nice light that spreads well.

$ is another issue though...

Starts far faster than any CFL flood Ive tried... Though these Philips ones start faster than the GE ones we have.

 

[Cujet]

I'd like to know your view on the brightness. If you have a light meter, you could use it to produce some objective data.

I'd guess that the CFL produces more un-usable light, due to the curly nature of the bulb.

I purchased one LED bulb from Costco for my "high hats". It is whiter than the Phillips 2700K CFL's. (The 2700K CFL's exactly match the 100W GE bulb I have up there too.

 

[The_Jeff]

What is the CRI on each?

 

[JHZR2]

Not sure if it is on the boxes. Don't have access right now.

Regarding brightness we have a couple of CFL floods in outdoor units on the outside of our house. One thing I've noticed with them is that they're quite slow to get up to full brightness. The LEDs definitely far faster. Practically speaking it means you have a lot more brightness a lot faster with the LED. Is a CFL dimmer or brighter than the LED in the same position? I'm not entirely sure. Compared to the older CFL floods I would say definitely yes but compared to the late-model GEN Phillips CFL floods running fully warmed? I don't know. What I can objectively say is that the LED light is just warmer and more filling into the space compared to the CFL. That doesn't necessarily imply anything about practical brightness though. But if I was lighting a space and had a choice between the two other than cost being an issue I would definitely go with the LED at this point just based on my experience. The LED is having it has a lot of metal in its design and that metal doesn't did get quite hot. Surprisingly so considering it's only dissipating 24 W. if that heat on the outer surface of the metal means that it's keeping the heat away from the electronics and is going to provide longer life I'm sure happy about that. Though it cost $40 unless I can quickly find a US-made 24 W LED I'll probably keep this one just to see how it works long-term. it's switched for lighting our basement stairs, so probably see a lot of on off use. It will be interesting to see how it holds up - I'm assuming it will do pretty well. Maybe that's a stupid and expensive assumption, but we really like the light that it puts out on tour stairway any straight down position - my wife really noticed the quality of the light and likes it too.

Would I put them in my outdoor lights on a motion sensor? No because they're both too heavy and too expensive. For an outdoor light that we turn on to provide lighting for a certain area and is switched and left on for a long time the CFL floods seem to be an okay selection. For lights that are used for courtesy purposes attached to a motion sensor it seems it incandescent floods really are the best way to go because of the start up time. LEDs really would be ideal for this because they start up so fast but they're just too heavy in my view and of course the cost is prohibitive. They would do well in that application though assuming that the on off characteristic of a motion sensor wouldn't kill the light prematurely.

 

[PandaBear]

Originally Posted By: tgferg67
The "equivilant" is probably a measurment of the directional light you will receive in this application. Lumens is an omnidirectional measurment and LED's are a more directional light source. In directional or downlight applications LED's seem more efficient per watt than fluoroescent. In a typical bulb/fixture where the light is coming from all around, lumens would be a more accurate measurement for comparison.


My cousin who works in the lighting industry said the biggest problem of LED lighting is heat, so yes, it is mainly as a heat sink.

 

[JHZR2]

Originally Posted By: PandaBear

My cousin who works in the lighting industry said the biggest problem of LED lighting is heat, so yes, it is mainly as a heat sink.


Thing is, a 23W CFL that disperses 1300 lumens I would imagine should dissipate roughly the same heat as a 24W LED that disperses 1300 lumens, especially in a bulb with the same form factor and beam pattern, like a PAR 38 flood.

Thus I would assume that the power electronics keep cooler?

 

[PandaBear]

Originally Posted By: JHZR2
Originally Posted By: PandaBear

My cousin who works in the lighting industry said the biggest problem of LED lighting is heat, so yes, it is mainly as a heat sink.


Thing is, a 23W CFL that disperses 1300 lumens I would imagine should dissipate roughly the same heat as a 24W LED that disperses 1300 lumens, especially in a bulb with the same form factor and beam pattern, like a PAR 38 flood.

Thus I would assume that the power electronics keep cooler?


The surface area that the similar power, similar lumen CFL can be very different. If the light of the LED is generated from a small area and then spread around, it can have a lot of heat in that area. In CFL the heat can be spread around the whole tube, so the heat density is lower.

Also different material have different heat sensitivity. Just because a CFL may work fine at 100C doesn't means the LED are working well at that temperature.

 

[JHZR2]

Agree. The LED is just an Si, Ga or Ge semiconductor, with a known maximum temperature.

Sure, the flux in terms of W/m^2 on the semiconductor die is much higher, but if the boundary condition is set as the entire bulb, the total heat generation should be about the same. However, the CFL is generally cooler than the LED after enough runtime to let it hit "steady state". At the end of the day there is only 23 or 24W coming in to create heat (instead of photons) for either kind of bulb, and so in the limit of the entire bulb assembly, the amount of waste heat should be equivalent to the power in which is known, times the overall efficiency.

Now it could well be that an LED makes the same number of photons with 5W as a CFL makes with 15W, but the circuts are different and the CFL circuit is more efficient, so the overall energy used is the same but the thermal dissipation in total is higher from the LED... I dont know.

What I do know is that the heat capacity for the LED is far higher and the surface temperature of the LED is far higher, making me think that overall, there is a difference.