CFLs or LEDs?

[Howard]

Power factor.
A resistive load, like a lightbulb, uses the power immediately when it's available.
A load with a power supply in it is going to be capacitive, inductive, or both. Capacitive acts like a short circuit until the capacitor accumulates some charge. Inductive acts like an open circuit until it's pushed out a magnetic field.
So what you end up with is that the load "looks" like it needs X units of power, but when the power company goes to all the trouble of making that electricity available to it, the load goes "Nah, I'm good. I'll only take some of it."
What it ends up looking like is that you had a 100W load, and sufficient power was available for that, but only 70W was actually needed. You still incur the usual line losses for that unused portion.
Residential customers won't get billed for this "extra" though. They only get billed for what they do truly use.
Directly.
It's paid for indirectly because the power company needs to have the infrastructure in place to accommodate the larger apparent load.

Power factor correction circuitry makes the load act, from the power line's perspective, like a resistive load. It's also usually an extra cost, so a manufacturer won't add it unless:
a) They care about just helping out in general, in that little way and it won't add much cost.
b) They're trying to meet a spec.
c) Their marketing department thinks that their target audience will not mind the extra expense if it means that they get to see "PF: >0.97" on the package.


Outdated sources.
In the industry I'm in, some customers come to us for product, but they're trying to meet specs that were written back when white LEDs were newly available. They specify a certain brand, color temperature, brightness, and viewing angle. They're all very narrow angle parts, with very blue, low-quality light. It is that way simply because that's all that was available at the time.
"Which white LED do we want to use in this?"
"How about we buy the only one in existence?"
"Oh, yeah, right. Good idea."

Now you've got color temperatures available from 2700K up to 16000K and beyond. Cheaper ones will also stray a good distance away from the blackbody curve. You get a light that looks like it's trying to stand next to the friend of somebody who owns a white light, but you can see that it's definitely not white.

So there's some work there to be done to meet what the spec wanted. In some cases, meeting it exactly isn't really possible, because the original manufacturers either don't make the part anymore, or they themselves are no longer around.

http://sound.westhost.com/lamps/index.html

http://sound.westhost.com/articles/incandescent.htm
http://sound.westhost.com/lamps/cfl.html

 

[Micrornd]

CFL's normally require a more expensive "CFL compatible" dimmer, rather than a standard incandescent dimmer or they flicker.

If you have a fixture with multiple bulbs (like in the dining room, etc), you can use CFLs in it with just a standard incandescent dimmer by simply using 1 incandescent bulb and all the others can be CFLs.

It works with any number of CFLs, as long as you have that 1 incandescent in the mix.

 

[Jeff7]

In small spaces with lots of bulbs incandescent bulbs most certainly do affect the ambient temp, my wife always complained how hot it was in the bathroom doing her makeup/hair/whatever until I replaced the 8 incandescent bulbs with CFL, it's perceptibly cooler now...one bulb here and there no, in that specific instance absolutely yes

Those incandescents are also whacking you with a lot of infrared photons, so you'll have a fair amount of radiative heating. CFLs do a lot less of that.

 

[destrekor]

It's actually rather mesmerizing just how inefficient even CFL and LED bulbs are. Both require a built-in power regulation/control method, and that's still not the only source of energy loss, considering, in LED, the juice still has the actual circuits to traverse and the numerous individual LEDs to saturate and force to produce light.
In CFL, I think it's only the power/ballast where energy is lost... but I have no idea regarding the post-ballast energy efficiency of the CFL tube/gas itself.

We have a long ways to go - what can come of increased energy efficiency within silicon circuits (or silicon circuits getting replaced entirely, as has been discussed before) can barely be imagined.

 

[Imp]

It's actually rather mesmerizing just how inefficient even CFL and LED bulbs are. Both require a built-in power regulation/control method, and that's still not the only source of energy loss, considering, in LED, the juice still has the actual circuits to traverse and the numerous individual LEDs to saturate and force to produce light.
In CFL, I think it's only the power/ballast where energy is lost... but I have no idea regarding the post-ballast energy efficiency of the CFL tube/gas itself.

Go check out some of the Philips spec sheets / manuals for LED bulbs. The maximum temperature for a bulb I have is apparently over 100 C. If these are "efficient", the inefficiency of incandescent bulbs, in terms of light production, is pretty abhorrent.

 

[edro]

Incandescent are around 15 LPW, CFLs and LED are 60-80.

LED can get much higher than that though... it's just a matter of time.
CFL is capped where it is.

 

[Jeff7]

Go check out some of the Philips spec sheets / manuals for LED bulbs. The maximum temperature for a bulb I have is apparently over 100 C. If these are "efficient", the inefficiency of incandescent bulbs, in terms of light production, is pretty abhorrent.

This.

LEDs are certainly getting better, but if you look at the amount of usable light you get out of the things, compared to the amount of energy that goes into them, you still have a lot of it getting converted into heat in the emitter. LED dies tend to experience a lot of internal refraction, so diemakers have to figure out ways of convincing the light to get around to exiting the die, rather than being absorbed internally. The material itself also experiences power losses due to internal resistance. White LEDs are made with a blue emitter. The light hits a phosphor coating. Some passes through. Some is absorbed and reemitted. Some is absorbed and turns into heat.
But it's still a hell of a lot better than incandescent.

Using a heated filament for light, rather than heat, is like buying a $100 used car so that you can make toast on the engine block, and then do nothing else with the car. Yes, it will certainly serve that purpose, but it's not a very good solution.


Concerning the regulation, if you have good quality circuitry there, it's possible to get high efficiency. High-power LED drivers can do better than 90% efficiency. Simple little switchers can go beyond 80% (PDF). Or, cheap-junk switchers can approach the efficiency of heavy old wall-wart transformers. If you take the most efficient LED in the world and strap it to a crappy power supply, the whole system's efficiency suffers severely, and you might be just as well off with an incandescent bulb, once the cost of the LED bulb is factored in.

If you've got a DC system, some DC-DC converters can give very good efficiencies, somewhere north of 95%.

 

[destrekor]

Go check out some of the Philips spec sheets / manuals for LED bulbs. The maximum temperature for a bulb I have is apparently over 100 C. If these are "efficient", the inefficiency of incandescent bulbs, in terms of light production, is pretty abhorrent.

Well absolutely.

In reality, we've made HUGE strides toward how much true lumens per watts (after all waste and actually getting into use as light output) we can produce.

Electrifying gasses and these things called LEDs, even after having to include a throw-away energy converter and regulator, is a heck of a lot more energy efficient than simply throwing the household electrical grid at an exposed piece of tungsten wire within a sealed environment. That doesn't particularly sound like a grand source of efficient light output. Hmm, you mean, if we put so much energy across this piece of wire, it not only produces an epic amount of heat, it glows really bright, enough to light a room!

I mean, obviously that's not to discredit the invention or anything, lol. However, it was a by-product event (that is, the light production) - in reality, it was just a resistor that could be put on display. It was a terrific leap at the time, but we're obviously much more capable of better efficiency now that we know so much more, thanks to that early work as a head start.

 

[who?]

Is that the maximum temperature it makes or the maximum enviromental temp. that it will work in?

 

[Jeff7]

...
I mean, obviously that's not to discredit the invention or anything, lol. However, it was a by-product event (that is, the light production) - in reality, it was just a resistor that could be put on display. It was a terrific leap at the time, but we're obviously much more capable of better efficiency now that we know so much more, thanks to that early work as a head start.

And of course, so were LEDs.

Then: "Huh...this exposed diode is glowing ever so slightly. Interesting."

Now: "WARNING: Looking directly at the emitter can permanently damage your eyes.

 

[who?]

Also if the LED has less mass that high a temp. doesn't require as much energy to get to as is required with a tungsten filament. Temperature does not equal energy.

 

[destrekor]

And of course, so were LEDs.

Then: "Huh...this exposed diode is glowing ever so slightly. Interesting."

Now: "WARNING: Looking directly at the emitter can permanently damage your eyes.

doh!

 

[RossMAN]

Assuming these are the same price, which is the better bulb and why?

Uses: regular table lamp connected to a Belkin WeMo, recessed cans and bathroom vanity lights. Could care less about dimming.

http://www.homedepot.com/p/Philips-...d-Dimmable-LED-Light-Bulb-E-424382/203553310#

http://www.homedepot.com/p/Cree-60W...ht-Bulb-BA19-08027OMF-12DE26-2U100/204592770#

 

[DaveSimmons]

Assuming these are the same price, which is the better bulb and why?

Uses: regular table lamp connected to a Belkin WeMo, recessed cans and bathroom vanity lights. Could care less about dimming.

http://www.homedepot.com/p/Philips-...d-Dimmable-LED-Light-Bulb-E-424382/203553310#

http://www.homedepot.com/p/Cree-60W...ht-Bulb-BA19-08027OMF-12DE26-2U100/204592770#

In my limited research those are the two brands I've seen most often spoken of as "good" brands vs. others.

The main difference is the Phillips is brighter: 11 w / 880 vs 9.5 w / 800.

I just got one of the Phillips bulbs from Amazon today for the desk lamp in my home office but haven't tried it yet.

 

[killster1]

Considering the awfulness of non-dimmable CFL's, I don't think you could pay me to try dimmable ones. After the tenth one buns out I'm gonna start breakin' shit.

I'm curious about LED's, though. I was gonna say that LED dimming was feasible, but would require an array of lights and not 'dim' so much as just have multiple brightness levels.

I still use incandescent bulbs. Suck it, environment.

is there any logic to the bs coming from your mouth!!!! i use cfl and LED.. LED bulbs are replacing my CFL (about 6$ each) as they go out.. i really like CFL but my lovely gf is against them so i will phase them out.

 

[Squisher]

I've gone CFL when I don't need dimming and LEd where I do. The only thing I see are that some dimmable LEDs don't like certain voltages and flicker at them (like at 95% power), but this is easily curable by adjusting the dimmer setting.

Someone really needs to drive down the cost of larger LEDs, right now the 60 watt equivalents are under $15, but try to find something in the 90 watt equivalent range and you're looking at ~$40.

 

[shortylickens]

I've gone CFL when I don't need dimming and LEd where I do. The only thing I see are that some dimmable LEDs don't like certain voltages and flicker at them (like at 95% power), but this is easily curable by adjusting the dimmer setting.

Someone really needs to drive down the cost of larger LEDs, right now the 60 watt equivalents are under $15, but try to find something in the 90 watt equivalent range and you're looking at ~$40.

supply and demand.

When people realize how good they are then production will ramp up. They just arent common enough yet.

 

[destrekor]

I've gone CFL when I don't need dimming and LEd where I do. The only thing I see are that some dimmable LEDs don't like certain voltages and flicker at them (like at 95% power), but this is easily curable by adjusting the dimmer setting.

Someone really needs to drive down the cost of larger LEDs, right now the 60 watt equivalents are under $15, but try to find something in the 90 watt equivalent range and you're looking at ~$40.

That's the unfortunate thing, the major advances in LED production have been limited to the lower wattage, more commonly-sold wattages.
It'll be awhile for the brighter bulbs to trickle into the market, at least from Cree and Philips.

It was only just recently, I think, that Cree started offering a 75w model. Well, I take that back - it's still not offered in-store at Home Depot, nor are the TW series, so those could have even been available when I bought the ones I do have. Which would be aggravating, considering I'd skip to buying the TW series right now if I could. I was hoping to buy some in store though.

I do see Philips has quite a few different types of bulbs even at 100w, but you are correct, the pricing is right around what you said. I suspect it's the same thing though - they either don't sell those enough to bring economies of sale into the picture, or they haven't sold enough/found some reason to justify designing a more cheaply-produced model.


Also, regarding dimming:
it can be directly blamed on the bulb, but more likely, specific dimming performance will probably be a result of the dimmer used. While LEDs are far more compatible with dimmers than CFLs, in general, LEDs still have a temperament and don't work well with the electrical designs of certain dimmers.

 

[William Gaatjes]

Best theoretical efficiency for a led lamp would be if you had a string of leds right on the mains power without current limiting resistor or smps power supply to regulate for a constant current through the led. But in reality you need a smps to transform the mains voltage of 120VAC or 230V AC to around 3,5 V DC for a single led.

The most powerful led lamp i have is one from Philips. It is an 11 watt led lamp that is equivalent in brightness to a 60W to 75W incandescent lamp. It is set up as 3 individual led lamps in a 120 degree angle inside a milk glass bulb.

The least powerful led lamp that i have is 1,2W but i have a couple of those in a lamp and combined, do have a sufficient room lightning capacity. Yet less then 10W total.

All my led lamps are warm white.

 

[William Gaatjes]

I almost forgot, the leds may function 20 years, but be prepared that depending on the components used, the electronics inside a ledlamp may not function for 20 years. Especially if Electrolytic capacitors are used under high temperature and high ripple current. Ceramic capacitors however will function indefinitely when used according to specification.

 

[William Gaatjes]

Most led lamp drivers have a pfc on board and draw a overall sinusoidal current in phase with the mains voltage. For a smps ledlamp that is easy to do, to integrate an power factor corrector.

 

[Bateluer]

Right now, my entire house is CFLs. I thought about switching to LEDs as they burn out, but these CFLs just don't burn out; been installed since 2006 or 2007. Crazy how long they last.

 

[destrekor]

Right now, my entire house is CFLs. I thought about switching to LEDs as they burn out, but these CFLs just don't burn out; been installed since 2006 or 2007. Crazy how long they last.

Must have got some good CFLs at the time, I'm frankly amazed.

Well, then there's this: do you turn on any (any that are currently still alive from 2006/2007) of them on/off more than once a day?

 

[AstroManLuca]

CFLs are terrible. They're a cheap stop-gap solution but there are so many drawbacks.

They have a warm-up time, which isn't so bad at first but it gets progressively worse over time. CFLs I've had for more than one year are almost useless until they've been on for a minute or more.

Obviously they are totally unsuitable for outdoor applications. Got a $10 LED bulb for our outdoor light, amazing. Comes on instantly, super bright white light, even in sub zero temps.

They're so sensitive to being turned off and on that they last far less time than advertised. They don't die quickly, either, they just take longer and longer to warm up until you eventually notice that your lighting sucks. Worst possible light in rooms where you don't leave the light on for long, like bathrooms.

Because they are sensitive to on/off cycles, you then have to choose between leaving your lights on and wasting energy, or turning them off and shortening the life of your bulbs, which is also a waste of the energy and materials used to produce them. Not to mention all the hazardous chemicals that exist inside.

Way I see it, CFLs are the Priuses of light bulbs. You THINK you're doing good, but you're not. LEDs are the Leafs of light bulbs. I just wish they weren't so expensive. But once my supply of CFLs runs out, I'll probably start replacing them with LEDs. Or at least I'll try.

 

[edro]

LED lamps replacements over 60W are rare because of heat.
It's difficult to dissipate that much heat out of such a small package.
As LEDs get more efficient, ~800-1000lm will create less and less heat.