What about LED bulbs? How do they fare with dimmers?

LEDs need some more advanced circuitry (pulse width modulation), but since they're fully off for some fraction of the time, it ought to consume less power in that state. The Eternalight flashlight does this to save batteries quite effectively.

Best dimmer is a candle.

Missed a chance to make a "dim bulb" joke too.

I came across a CFL bulb today that you can use with a dimmer - one of the first in the UK, so far as I can tell:
http://thegreenguy.typepad.com/thegreenguy/2007/04/the_energysavin.html

I appreciate dimmers aren't ideal, but if you've moved to a house that already has them installed, surely - I'm guessing - it's greener to keep them in rather than ripping out to replace with more plastic and electrics?

For CFLs, I'm pretty sure the ballast can be upgraded to be compatible with a dimmer switch. In combination with dimmable CFLs, this seems to be a workable alternative. No?

The Ballast in a CFL can't be replaced, part of making it compact is squeezing everything into the base of the bulb makes replacing the individual components not easily replaceable unless you have a small solderign iron.

I'm fairly certain the ballasts are magnetic, because they are cheaper...and it also provides the hum if any. Electronic ballasts can dim i believe.

In terms of energy efficiency, it's even worse than you think. Incandescent bulbs put out only 6% of the power put into them as visible light, the rest being infrared (heat). Dimming works by dropping the temperature of the filament, but that shifts the blackbody radiation curve even further into the infrared, so that less of the total percentage of power is going into the visible part of the light spectrum.

On the other hand, dropping the filament temperature also increases the lifetime of the incandescent bulb; the estimates range anywhere from 4 times to 20 times, though I'm sure that depends on the degree of dimming.

I'm not following your logic.

Dimmers reduce energy consumption a little, or not at all, but they don't increase consumption. So, how can that be any worse than not using a dimmer?

If it's between using a dimmer and not using one, it seems using one conserves more energy. Even if it's not awesome at it, it's still better than nothing.

I'm not following your logic.

Dimmers reduce energy consumption a little, or not at all, but they don't increase consumption. So, how can that be any worse than not using a dimmer?

If it's between using a dimmer and not using one, it seems using one conserves more energy. Even if it's not awesome at it, it's still better than nothing.

That's all well and good, but if you want CFLs to take off with the mainstream, they have got to be friendly to mainstream lifestyles. One of the biggest roadblocks for CFLs in the beginning was the poor light quality. The quality of light has drastically improved, and thus you see a huge gain in popularity of CFLs.

The fact is, there are a heck of a lot of dimmer switches in the US and not that many people who would be willing to pay an electrician to set up extra circuits for their lights just to get rid of their dimmer switches. (Not to mention all of the renters who are not allowed to do such things). In the mean time, all of those light sockets still have incandescent, even if many people want to switch. If we want to see an even wider use of CFLs, they're going to have to improve the quality and availability of their dimmer-compatible lights. It isn't just about what we treehuggers are doing -- we've got to get the country on board.

That's great that you were able to set up separate circuits for your lighting, but that isn't an option for everyone. And even you said that dimming a light does reduce energy usage slightly, though not well. So dimmers do help a bit for people who aren't ready or able to adopt your solution.

bfos, I think you are both right. From an efficiency point of view (how much bang for your buck), dimmers are not ideal.

From an end result perspective, they are probably better than nothing.

Best would of course to invent/use something that is the best of both worlds. Not sure what it is.. Maybe dimmable LED bulbs?

A better solution than a dimmer would be a three-way bulb. You get mood lighting and a reading light in one bulb. Of course, they only work in lamps and not light fixtures.

So what's a romantic treehugger to do? (Especially one who lives somewhere they're not allowed to use candles.)

I can't beilieve that that whole discussion took place without any mention of aesthetics and atmosphere. Let me tell you when I am noodling on the sofa with my hubby I need less light than when I am reading the New York times on said sofa. Now that is a an unrealistic comparison, because of course soy or beeswax candles would be ideal for the first case. But a house is a machine for living, not just working, but working, socializing, playing, doing homework etc. Not all of these activities require the same amount of light. Dimmers are a very effective way to get many lighting situaltions out of the same fixtures. Perhaps if our only qualification for quality in lighting is lumens per watt, dimmers are bad, but as a system to functionally light a life, dimmers are helpful. It is not all engineering.

As a migraine sufferer, I LOVE dimmers. I get migraines that render me extremely photosensitive. I have been seeking out CFL / LED bulbs that dim for this reason, and this reason only. The flicker of a candle flame can be extremely irritating to a migraine. The soft glow of a light bulb is not, and I find that even later in the evening when my eyes are tired, the dimmed light is much easier on them.

I do not want to be wasteful at all, and frankly feel very ignorant that I didn't know that having incandescent bulbs dimmed used up just as much energy as they would use being on full blast. However, that does not take away my need for dimmers. While frequent chiropractic care has greatly reduced the number of migraines I get, I still rely on my dimmers and they are the only seven lightbulbs in my house that have not been converted to CFLs.

I have found the large recess light bulbs and the small chandelier-like tapered bulbs in a dimmable version at The Home Depot, but am still waiting for the regular size (I need standard size bulbs and small recess bulbs for eyeball lights, not standard recess cans).

However because I don't like not having all the bulbs in my house converted to CFLs, I offset these bulbs and my car through Native Energy wind energy credits.

There seems to be much misinformation out there as to dimming of CFL's, as previous posts have quite rightly said. Different dimming cfl's have been designed to work on different dimmers such as leading edge or trailing edge, if one has been designed for one, it wont work on the other. This has prompted a lot of manufacturers to simply drop the promotion of dimming globes. The re-education of the masses is simply not possible.

Our company Neco is a specialist in energy efficienct lighting and we have tested nearly all of the variable dimmable CFL's there are.... they all have issues of some kind which is why we dont sell them. becuase half will come back!

However, there is a fascinating new technology made by Megaman that overcomes all dimming issues. It's called 'step dimming'. The theory is that EVERY globe in a home can be dimmed on A NORMAL on/off type swtich, without the need for a dimmer wheel (yes they are obsolete in my opinion) - If you rapidly turn the switch on and off (in under 3 second intervals) the lamp steps through one of 4 dimmed light settings 100%, 66%, 33% and 5% and then repeats the cycle. If you want to keep the same light setting, you just turn it off and then back on again later an d it will maintain the light level. They only cycle to a different light setting if you turn the switch on and off in under three seconds.

I am sat underneath one right now, no flickers, buzzing from the dimmer wheel on the wall (becuase its just a normal switch!) I have run a meter on it and the wattage consumet on the lowest setting is about the same as a very expensive LED with the same amount of light.

I think these are the way of the future - you can check out the 240 Volt versions (UK and Australia) at http://www.neco.com.au/product.asp?pID=638&cID=47

I am not sure if Megaman make US/Can/Jap Voltages yet but have a go at asking them - www.megaman.cc is the main site.

Anyway, lets all say an educated bye bye to dimming wheels with their annoying buzzing and propensity to catch alight when they become old!

Bring on step dimming for all.!

OK, but y'all seem to have missed the bigger picture....
Mood Lighting.
I mean, have ou ever tried to put on the moves under fluorescent lighting? (envision the sickly lighting of your office cubicle and how attractive it makes everyone look.) ugh. It ruins the date every time. And, yes, the flicker of candle light is great but, sometimes, not enough unless the room isfilled with burning candles, in which case you better have a fire extinguisher handy....
I hope we can all do our parts to be as green as possible and move humanity (kicking and screaming) in that direction but, let's not forget that we need to have some fun along the way and, THE MOVES work better with SEXY lighting!

SAVE the planet, share the LOVE and, save the SEXY LIGHTING!
Cheers
C

OK, but y'all seem to have missed the bigger picture....
Mood Lighting.
I mean, have ou ever tried to put on the moves under fluorescent lighting? (envision the sickly lighting of your office cubicle and how attractive it makes everyone look.) ugh. It ruins the date every time. And, yes, the flicker of candle light is great but, sometimes, not enough unless the room isfilled with burning candles, in which case you better have a fire extinguisher handy....
I hope we can all do our parts to be as green as possible and move humanity (kicking and screaming) in that direction but, let's not forget that we need to have some fun along the way and, THE MOVES work better with SEXY lighting!

SAVE the planet, share the LOVE and, save the SEXY LIGHTING!
Cheers
C

Regarding dimming LED lamps: LED lighting is a technology still very much in its infancy, which is why LED lamps cost so much at present. I have little doubt, however, that LED lamps will eventually become the norm - they're almost another order-of-magnitude more efficient than CFL's, and more rugged, to boot.

Light Emitting Diode lamps are actually aggregates of many (e.g., 18 or 36) individual LED's, each about 3-4 mm in diameter. The light output of an LED cannot be varied much - they tend to be mostly 'on' or 'off'. But, since there are many in each "bulb", it will be possible to implement relatively simple circuitry to adjust how many of the array are illuninated - making it possible to have several discrete light levels. And, with each successive dimming, more electricity will be saved.

The other problem with non-dimming CFLs is they do not allow for timers either. CFLs work best when left on for a longer period of time (the on/off cycle is what burns out the bulb). With that in mind they work great for exterior security/driveway type lighting. Timers work great for exterior lighting as well, but CFLs don't work in a timer. You could by a new fixture that is a photocell, but again, isn't it better to make what you have better?

I have numerous recessed lighting cans in the ceilings of my 22 year-old home, and almost all have dimmable switches. I did not choose them - they came with the house. If anyone else is interested, I have ordered dimmable CFL bulbs, specifically for recessed can lights, from the following site. I believe you have to be a customer of a participating energy supplier to purchase from this site, but after you see the specific product information you may be able to find the same product elsewhere.

http://www.energyfederation.org/consumer/default.php/cPath/2050_25_44_169

What about mercury? I hear that the CFLs ave mercury in them. Someday we'll have mercury being spread throughout the landfills if that ia true.

Uh,

P = I^2.R
and
I = V/R

A resistance-based dimmer increases R, which linearly will decrease I for a given voltage. So cranking a resistance dimmer to "darker" will reduce energy consumption. Eg, say the resistance of bulb + "bright" dimmer = n Ohms. Then at 110V single-phase AC, power consumption (RMS) is 110^2/(n) -- crank up the dimmer so that resistance is now (n+m) and power goes to 110^2/(n+m) -- ie less power consumed.

I have a question about CFLs and dimmers, and since you all seem so knowledgeable on the subject, I think this might be an appropriate place for it.

My boyfriend and I are renters, which means that we do not get to make changes to our light fixtures/electrical wiring. In our dining room we have a chandelier that holds four bulbs and is on a dimmer. For the most part, we don't actually dim the lights in there; they're either on or off. I found dimmable CFLs, but they were very expensive -- much more than the regular CFLs and I heard mixed reviews (don't work that well, buzz, etc.).

So, my question is: can I use regular CFLs in a dimmable fixture, even if we're not dimming?

Please advise -- I don't know where else to look for help!

Thank you,
Ilana

If the dimmer switches doesnt work, try with Inderal. Its a beta blocking drug that is commonly used in the prevention of migraine headaches.

how about the Halo: H573ICAT1D...energy star rated for dimming with it's own dimming ballast?

Tidying up some issues: CFLs do have a tiny amount of Mercury. 4-6mg is common. A tiny fraction of that in a mercury amalgam mouth filling.Less mercury than would otherwise be liberated from burning fossil fuel to run a traditional light bulb. IMO, the amount is small enough to be safely ignored.

Technology is still driving better CFL lamps, even though the prices are already extremely low. Philips, GE and Osram are IMO best for colour rendering. I have had good Mazda bulbs with amazing lifespans. Chris: For white people, Osram tend to bring flesh tones out well with a strong magenta component to the light. Newer Philips are fairly good, older philips CFLs make you look a little jaundiced.

Regarding dimmers: Dimmers don't increase the frequency of the supplied power. They cut the waveform supplied to the bulb. At full dimming, only the last few degrees of waveform are supplied. The frequency is the same, the amount of time power is applied is reduced. As you dim a tungsten bulb, the total amount of power consumed goes down. At the same time, the efficiency goes down, as someone said, the black body curve moves from visible further into the infra-red.

Bare un-packaged LEDs can be infinitely dimmed with no drop in efficiency. in fact, an LED operates more efficiently at 10% power than at 100% power. The question is how should your light dimmer communicate your wish to dim the light to the LED current control circuit?
PWM? No. The control gear inside the lamp may be inductive or capacitive reactive. Unpredictable results, possibility of lights burning out. A PWM compatible lamp would use a resistive current limiter, and therefore be inefficient.
Waveform splicing? If the forward voltage is very close to the supply voltage, a dimmer will result in unstable brightness.
Voltage modulation? This will infer a DC circuit to the lights. Active control gear in the LED lamp can respond to varying supply voltage. Could possibly interface with waveform splicing dimmer, but will require complex circuit in LED bulb.
Current modulation? This is closest to what an LED needs, but the dimmer circuit will need to be made specially for an LED based system. By standardising on a max current per LED fitting, the amount of light output can be varied by changing the number of LEDs in series in the fitting. Multiple fittings can be operated by wiring them in series. Such a system will be incompatible with any other lighting technology but can be very effective and very economical with modern LEDs exceeding 100Lm/w.