Light fixture wattage limit and compact fluorescent bulbs

It seems like many modern light fixtures say that you should use no more than a 60-watt bulb. In doing some learning about compact fluorescent bulbs, I see that a 23 watt CFL provides around the same amount of lumens as a 100-watt incandescent bulb (1600, compared to 800 lumens from a 60-watt incandescent).
So it seems like I should be able to replace a 60-watt incandescent bulb with a 23-watt CFL and get twice as much light, while still staying well below the fixture's limit of 60 watts... Is that correct?? It somehow feels like cheating...
Thanks!
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Yep - if it says 23 watts, that's all it's using. With incandescent bulbs, most of that 100 watts (about 97 percent of the energy, IIRC) is just turned into heat. CFLs are obviously more efficient, turning more of the energy into light instead of heat. As you pointed out, they're about 4 times more efficient (1/4 the wattage for roughly the same light output), so you're still only getting about 90% of the electrical energy turned into light, but it's a lot better. And the color and warm-up time of CFLs has increased dramatically over the last few years, while price has decreased. I've gotten them on sale at Home Depot etc. for about $10 for a pack of 4, and some electric companies have rebates. LEDs are the next step - not many available for home use yet that I know of, (more in flashlights etc), but they're somewhere around 10-15 times more efficient than incandescents. I recently read something about micro-LEDs incorporated into wall paint, so a small current could be applied to a whole wall, which would give off a soft glow and almost no heat. No telling when or if that will become practical, but that's probably what people said about hybrid cars a while back... I almost exclusively use CFLs at home (incandescents for porch/garage, where cold temps can interfere with most CFLs), and I think they're definitely the way to go. Good luck, Andy
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snipped-for-privacy@yahoo.com wrote:

Generally 93-95%.

Better CF lamps are about 20% efficient at producing light, and the light is mostly of wavelengths selected for the human eye to be more sensitive to - which is why better ones have 4 times the luminous efficacy of incandescents when they are closer to 3 times as efficient at converting electricity to visible light.
So CF lamps are about 80% efficient at producing heat.
Actually, when it comes to heating the room, all lamps are closer to 100% efficient at producing heat, since most of the light will be absorbed in the room.
One thing to keep in mind: About half the energy going into an incandescent becomes infrared that passes through the glass, and presumably escapes the fixture as well as visible light does, and this is heat materializing in the room but not the fixture. So incandescents are generally around or somewhat under 50% efficient at producing heat that turns up in the fixture. Compact fluorescents are about 80% efficient at producing non-radiant heat - nearly twice as efficient as incandescents at heating up fixtures. Because of this, I would not use compact fluorescents of more than half the maximum wattage for a fixture that has a rated maximum wattage for incandescent lamps.
Now for another bug in some fixtures: Compact fluorescents are more sensitive to heat than incandescents are. Even if the fixture does not overheat, a higher wattage compact fluorescent can overheat in a small enclosed fixture or a downward-facing fixture. This is mostly a problem with compact fluorescents of wattage 20 watts or more. The Philips SLS 15, 20, and non-dimmable 23 watt (but not the 25 watt nor the dimmable 23 watt nor non-SLS models) are actually rated to withstand the heat buildup in recessed ceiling fixtures.

The best white LEDs on the market now have efficiency 2-3 times that of incandescents. There has been a lot of hype and half-truths about the efficiency of LEDs. In some specific applications other than household lighting, especially traffic lights, LEDs outperform incandescents in efficiency by a much larger margin. Details are in a web file of mine:
http://www.misty.com/~don/lede.html
Expect it to be quite a few years before LEDs are used to make regular household lightbulbs. For one thing, compact fluorescents are still more efficient than LEDs. For another, LEDs are prohibitively expensive for such use - with 1.2 watt LEDs costing a few dollars apiece. Another obstacle with high power LEDs is heat output - they are still 85 efficient at producing non-radiant heat and generally do not take heat well.
Meanwhile, I agree that compact fluorescent is the way to go in most applications.
- Don Klipstein ( snipped-for-privacy@misty.com, http://www.misty.com/~don/cfx.html )
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GREAT website, but didn't see much data on the relative efficiency of leds in home lighting, but I will look again
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That's because there are no significantly marketed general home lighting LED lightbulbs (equivalent to 40-100 watt incandescent) to get data from.
The most efficient significantly marketed white LEDs (last time I checked a few weeks ago) are Lumileds "Luxeon" "1 watt" models, with typical luminous efficacy of 37.6 lumens per watt with chip temperature 25 C, and about 34 lumens/watt typically in the more reasonable condition of heatsink temperature of 35 C. LEDs will need a ballast of some kind or another, and losses in that will result in overall luminous efficacy slightly lower still.
100 watt 120V 750 hour incandescents get 16.7-17.5 lumens/watt, and 60 watt 1000 hour ones get 14-14.8 lumens/watt. Better compact fluorescents get mostly about 60 lumens/watt.
- Don Klipstein ( snipped-for-privacy@misty.com)
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On 28 Dec 2005 20:54:21 -0800, snipped-for-privacy@yahoo.com wrote:

I'd like to see a TV that you apply to a wall like paint, and could be as big as the wall. Maybe not so impossible with modern technology.

Although there's a problem using them with X10 (the normal X10 light switches are actually dimmers, the relay-type switches require a neutral wire).

--
Mark Lloyd
http://notstupid.laughingsquid.com
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Yes and no. It is safe to do it, but the heat will likely shorten the life of the CFL. I read that somewhere... Just make sure you don't have a dimmer on the circuit unless the bulbs are designed for dimmers.
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yes, but: the widely available compact flourescent bulbs can be used in open indoor fixtures. at our house we put them into 4 and 5 bulb ceiling fan fixtures and really brighten up the kitchen and office. they are not for enclosed fixtures they overheat. read the installation restrictions on your particular bulb in fine print before you buy. other types including outdoor styles are available at higher price ranges. see interesting energy saving stuff like i bought at: http://www.energyfederation.org/consumer/default.php
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Romanoda wrote:

I know - ain't it great?! http://www.eere.energy.gov/femp/technologies/eep_compact_fluor_lamp.cfm
R
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