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caught an episode yesterday where they took 5 common household light bulbs :: incandescent, tube flourescents, CFLs, LEDs, and some other bulb with a different filament
then all were set up on a relay timer to turn on and off at a 2 second interval.
at then end of 2 months all were burned out except the LED which was still burning a week later when they terminated the experiment
they started out trying to bust the theory that you save energy by turning off the light rather than just leaving them on all the time. All but the tube flourescents had a warm up time of less than .1 second
Years ago there was a big to-do over inserting rectifier "buttons" into standard incandescent bulb sockets (under the bulbs) to make them run on DC power. It was supposed to save electricity and extend the bulb life.
Whatever happened to that?
Does it save electricity? (I would assume it extends the bulb life due to reduced flicker.)
That's an older episode, but a good one. They concluded that it's almost always better to shut off a light when leaving the room, even if only for a minute or two...
I don't think they factored cost of the equipment and wear and tear on the equipment in their analysis though, only the electrical cost. I think once you factor in the reduction of life span of switching florescent bulbs on, that rises to 15 minutes. I don't know if anybody has tried to factor in the environmental cost, of the mercury and phosphors, to see if that time goes up...
ChuckHutchings wrote: Years ago there was a big to-do over inserting rectifier "buttons" into standard incandescent bulb sockets (under the bulbs) to make them run on DC power. It was supposed to save electricity and extend the bulb life.
Whatever happened to that?
Does it save electricity? (I would assume it extends the bulb life due to reduced flicker.)
Were those really rectifier buttons, or soft start thermistors? Just full wave rectifying power to a light bulb won't change power consumption or flicker.. They work equally well on either polarity.. Adding a simple diode in series would cut power consumption.. Not in half though, as they are a non linear load.. But doing that on enough bulbs would have an impact on the transformer serving the house, as unbalanced draw on the positive and negative cycles will cause the magnetic field to saturate, and then the imbalance gets balanced out by generating heat in the transformer.. Not a good thing..
For a while there were soft start thermistor disks for light bulbs.. I don't think they were so much aimed at power conservation, as extending the life of the bulb, by softening the thermal shock on start up, though they probably saved some energy by dimming the bulb with a series resistance. I believe what happened to them was a few failures in the field resulting in them being quietly pulled from sale. Never good having your light fixture go up in flames...
-klb- wrote: I don't think they factored cost of the equipment and wear and tear on the equipment in their analysis though, only the electrical cost. I think once you factor in the reduction of life span of switching florescent bulbs on, that rises to 15 minutes. I don't know if anybody has tried to factor in the environmental cost, of the mercury and phosphors, to see if that time goes up...
Actually they did -- they hooked it up to a rig that cycled them on/off every two minutes (as I recall). For most bulb types there was no significant difference in bulb life.
thier results were based on comparing the energy used at warm up to the same amount of energy used in a steady state. The CFL, incandescent, LED and the other one( Idon't remember what it were) all had negligible differences with the LED having the best results. It's warm up time was something like .015 seconds
However, the tube flourscent that they used had a 23 second comparitive energy use. so unless you were walking in and out of the room every 30 seconds, it was always better to turn the lights off.
Yes, it was an older episode, but this was a cool one (as if there were any episodes that weren't)
The CFL and incandescent faired about the same in the on/off test, so the price difference in the two would seem to make the incandescent more economical
My recollection was that in the Mythbusters test, the CFL and incandescent failed about the same time, while other data suggests that if they were left on steady, the CFL should last 5 times longer than the incandescent. I believe it is this reduced lifespan from cycling the CLF and the subsequent replacement cost that produced the 15 minute break even number I have formerly seen for fluorescent lighting..
-klb- wrote: My recollection was that in the Mythbusters test, the CFL and incandescent failed about the same time, while other data suggests that if they were left on steady, the CFL should last 5 times longer than the incandescent. I believe it is this reduced lifespan from cycling the CLF and the subsequent replacement cost that produced the 15 minute break even number I have formerly seen for fluorescent lighting..
- Kevin
Yeah, CFL's don't do well if cycled too much. But of course, if you leave them burn (compared to an incandescent that's only on when necessary), that can quickly negate any savings in the lower wattage...
Bottom line for me is: I endorse conservation and being a responsible steward of resources, but I don't want the government (or anyone) telling me what lighting technology I can and cannot use in my own home. Seems I should be the judge of what's the best bulb formy application... (I hope that isn't too political for PC, but it's how I feel).
-Tim
Last edited on Thursday March 27th, 2008 08:28 pm by tfischer
In the last few months we have found some CFL's that are acceptable in color balance for general use, and put them in most of the places where we put any significant hours of use, which really was not that many places. We have probably converted fewer than 1/3 of the bulbs in the house, but accounted for probably 90% of the lighting use. But there are some places like over the bathroom sink where I don't want to risk messing up the color rendering for my wife... Some time I'll have to break that up into separate his and hers light fixtures, instead of the existing row of 8, 40 watt bulbs...
In the last few months we have found some CFL's that are acceptable in color balance for general use, and put them in most of the places where we put any significant hours of use, which really was not that many places. We have probably converted fewer than 1/3 of the bulbs in the house, but accounted for probably 90% of the lighting use. But there are some places like over the bathroom sink where I don't want to risk messing up the color rendering for my wife... Some time I'll have to break that up into separate his and hers light fixtures, instead of the existing row of 8, 40 watt bulbs...
- Kevin
I've explained my aversion to CFL's here many times: You can't dim them (at least properly, with standard dimmers), and the warm-up times drive me nuts. And they're ugly, if they're not in a fixture which hides the bulbs (we have a lot of 'decorative' fixtures).
I bought some "dimmable" bulbs and they were a joke -- I put one in one of our recessed cans, left the other on the same dimmer incandescent. The as I slid the dimmer from 100-0%, the incandescent followed basically linerally. The CFL dimmed barely noticably as the dimmer went from 100 to about 20%, then shut off. I returned the bulbs...
Still, we've swapped out a number of bulbs around the house. Our entryway lights stays on a lot and I switched them to CFL. It's really annoying to come home, flip the switch, and get the equivalant of about 20W of lights for the first 4-5 minutes... Once the thing is warmed up though it is VERY bright... I wish they could figure that problem out (maybe LED's?)
I think with CFL, dimmable is just a way of saying that they won't die an early death if they are connected to a dimmer....
At least now days, the CFL's don't flicker on and off a few times on start up, like many of them used to do. I do agree that some of ours have an annoyingly long start up time. Interestingly, they are the ones that are installed at an odd angle... One is a flood light in a recessed fixture tilted towards a wall. The other 4 that are slow to start are in a ceiling fan fixture where they are tipped about 30 degrees down from being horizontal.. The rest of them (they are all the same brand) seem to start up at least 50% brightness, and warm up fast enough it doesn't bother me...
-klb- wrote: At least now days, the CFL's don't flicker on and off a few times on start up, like many of them used to do. I do agree that some of ours have an annoyingly long start up time.
I'd actually much rather have a bulb go <blink> <blink> <full brightness> than not blink, but go from 30-100% brightness over 5 minutes...
Cold seems to really effect their startup times as well. The recessed can in our entryway gets cold (I should really get up above there and put in more insullation) and that's one of the worst-offending bulbs for startup time (and unfortunately also the one I'd want to start up the quickest...)
I have CFL's in probably half of the fixtures in the house that will accept them, and about 60 percent of my blowmolds. Yet I have never suffered this "slow start" problem. I have several different brands, including the Wal Mart brand. I think you could be right, cold may be a factor in it, it does not drop down much around here.
____________________ People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf. -- George Orwell
Temperature definitely has a role in how fast they start, So does the amount of mercury in the tube. I think they have really cut back since the days of the ones that blinked a time or two on start up... I would not be surprised though if even today there is some variation in the amount of mercury in the bulbs from batch to batch, or brand to brand...
The information below is from OSRAM Sylvania regarding their CFL's in both the commercial two or four pin design as well as the ones that are either spiral shaped or spiral inside a plastic globe that looks more like a conventional bulb. Hope this clears up some of the confusion
Caution: DULUX EL units cannot be used on dimming circuits, emergency exit fixtures or lights, electronic timers, photocells, lighted switches or any other switches that do not meet UL20 Sec. 7.6.15. In outdoor applications, use only in enclosed fixtures to avoid exposure to weather. Use only on 120V, 60 Hz circuits. Never disassemble or modify lamp. Install or remove unit from fixture by grasping plastic base. Best performance achieved when operated at 77degrees F (25 degrees C). 40 Watt lamp is designed for base down orientation only.
The life ratings of fluorescent lamps are based on 3 hr. burning cycles under specified conditions and with ballast meeting ANSI specifications. If burning cycle is increased, there will be a corresponding increase in the average hours life.
Minimum starting temperature for DULUX EL lamps is 0 degrees F
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
"Minimum Starting Temperature" simply means the bulb will strike an arc and start glowing. It doesn't imply (to my knowledge) anything with regards to how much of the bulb's full brightness it is at the instant it starts glowing. I don't have a light meter, but my guess is the flood-style we are using (granted they are relatively cheap-o ones from Sam's club) light up at about 30-40% of their full brightness, after a minute might be up to 80% of their brightness, and up to 100% after 4-5 minutes. That's a long time when you're walking in a dark house and flipping on the lightswitch by the door...
But I have been living with that. My main complaints are the lack of dimming, and the appearance of the bulbs themselves when exposed. I'm fine with the light spectrum of the CFL's we're using -- but we have numerous fixtures (like the bathroom vanity) that use exposed clear incandescent bulbs. I know they make a CFL opaque equivalant, but I think they're butt-ugly (no offense if anyone here uses/likes them). And that's not even including the huge warning label on the side of each bulb that looks to be non-removable, but would certainly be exposed in our application... Sure I could rip out those fixtures and replace them, but where's the cost-savings benefit in that?
-Tim
Last edited on Thursday March 27th, 2008 11:53 pm by tfischer
