Compact Fluorescent Lamps (CFLs): Who Uses 'Em?

<div class='quotetop'>QUOTE(Proco @ Jan 4 2007, 06:05 AM) [snapback]370646[/snapback]</div>

I worried about this issue when we started conversion, but my understanding (probably ultimately based on industry sources) is that a day under fluorescent lights gives you about as much UV as a minute in bright sunshine. That has the sound of an industry-sponsored sound bite, doesn't it? Probably is. But even if they lied by a factor of 10, that didn't seem like a lot of exposure.

Then again, maybe I should look again.

First, this is a well-documented issue for some people with known sensitivity. People with lupus who are already photo-sensitive will show measurable disease flare-up when exposed to unshielded fluorescent lights. (Google it and find any number of sources). So, for for the very sensitive, yes, the UV from a fluorescent is enough to trigger the disease.

Second, there is a fairly large medical literature on the potential relationship between fluorescent exposure and skin cancer or cataracts. The National Library of Medicine (PubMed) lists quite a few articles:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?
db=pubmed&cmd=Display&itool=abstractplus&dopt=pubmed_pubmed&from_uid=6619386

My take on it, from a cursory look, is that most studies find no link, suggesting that any impact of fluorescents would likely be pretty small. I did not find any formal "meta-analysis" to bring all the studies together and reach some systematic conclusion. That's just my impression.

Third, however, at least in test tubes, cool white bulbs have been shown to damage cell DNA. That would be the second step (after the epidemiology above) toward demonstrating an actual causal link between fluorescents and skin cancer. So that's suggestive that it's not beyond the pale to find some impact.
http://www.pubmedcentral.nih.gov/articlere...6&tools=bot

Fourth, based on this source, a fair bit of the output of traditional fluorescent tubes escapes as UV. More than I would have guessed, anyways. Says here 3 to 6 percent of the wattage of the bulb comes out as UV (mid-1990s article). That seems like enough to be worth worrying about. In traditional straight tubes, most of the UV leakages come from the ends. Did not see a comparable measurement for CFLs, but I'd guess it would not be any higher than that.
http://www.anapsid.org/uvabstracts.html

Fifth, in ultrasensitive (ie museum) situations they do in fact worry about the UV output and take precautions. My understanding is that most glasses and plastics absorb a significant fraction of UV, so any fixture other than a naked bulb would keep the UV down. Museums apparently use special plastics to absorb all the UV.

So, my bottom line is, I don't know. I wouldn't dismiss the issue -- UV damage is cumulative. But I'd be wiling to bet I get substantially more UV exposure from daylight each day than from the fluorescents in my home. It's clear the very sensitive people have a problem with unshielded fluorescent bulbs.

Let me do a back of the envelope calculation, for sitting 2 feet away from an unshielded flourescent bulb that puts out as much light as a standard 100-watt incandescent.

EDIT: messed that up the first time, here's a revised and more realisic calculation:

A 100-watt incandescent bulb could be replaced by a roughly 25 watt CFL. But of that 25 watts of electricity into the bulb, you only get (maybe) 5 watts of light energy out. (Actually, that's optimistic: 5 watts of light energy would be about 3,000 lumens, which would be a very bright bulb).

Anyway, start with five watts of light energy. Assume that (upper limit) 6% of light from the bulb is UV. Assume you stand 2 feet from that bulb, and spread the light out on a sphere 2 feet in radius, so that you are measuring light intensity in watts per square foot.

How does the intensity of that UV exposure, from standing 2 feet from a bright leaky unshielded fluorescent, compare to full sunlight?

Full sunlight is 1000 watts/square meter, more or less. Looks like a typical value for UV energy as % of total spectrum is about 5%, at the earth's surface.

When I do that calculation, I find that a minute in bright sunlight gives you the same UV exposure as 15 hours sitting 2 feet from that bright leaky unshielded fluorescent.

For comparison, the intensity of UV in sunlight is roughly 5.5 watts/square foot. The UV intensity from the fluorescent bulb is about 0.006 watts/sq foot, or 1000 times less. NOTE that that is due almost entirely to the fact that sunlight is about 1000 x brigher. A quick check from other sources suggests that's about the right magnitude, ie, sunlight is about 1000x brighter than the light standing a few feet from a lightbulb.

In effect, the only reason you don't get a sunburn from a leaky fluorescent bulb is that it's so weak compared to the strength of sunlight.

So, if all those input figures are right, and unless there's something radically different about the UV spectrum from fluorescents versus sunlight, I think I have to agree with the industry sound bite above. And, of course, if you put the bulb in some kind of enclosure, the UV escape is reduced. (Which is also why the plastic enclosures around UV bulbs tend to turn brown and crackly after a while, I think.) And I'd bet that 6% is an upper bound for the UV broadcast by the bulb. And so on and so on.

But bottom line, the order of magnitude suggests the industry sound bite seems about right, based on my direct calculation from the data. Lifetime cumulative exposure still might amount to a fair but of extra UV. And for sensitive individuals it clearly can matter. But my calculation suggests that your total exposure from fluorescents is going to be small relative to your total exposure from sunlight. Not neglible, but small.

 

right now i live in a 118 unit apartment complex and all the installed lighting is CF. we add another 8 lighting sources. two are dimmer-touch lamps for the bedroom with 25 watt incandescents. they are only used for middle of the night adjustments. i have a spot CF reading lamps that is 14 or 12 watts. cant tell, looking at it right now and its not forthcoming although the socket says 8, 12, 14 watts capacity and a "company" torch lamp. it has a 100 watt bulb and is really too bright for normal use, but its the only method we have of creating light that covers the dining room living room area. otherwise, its pretty dark in there other than the spot CFs that we use for normal life.

 

Actually, I did not see the "other" option in the poll, so voted in the category that most fits how we use them which is the "use them in about half of my lighting for 4 - 9 years."

Actually, we use CF lamps in probably 75% of the most commonly used lights in the house. I bought them from http://www.fullspectrumsolutions.com/ My wife does not like the color of the light, otherwise, we would probably use them everywhere. If it were totally up to me, I would use them to replace all our incandescent lighting.

When I first bought them, I found myself thinking "where is that daylight coming from," and then realized that it was the CF lighting.

All the best,
Matthew

 

<div class='quotetop'>QUOTE(chogan @ Jan 4 2007, 07:54 AM) [snapback]370687[/snapback]</div>

Chogan, well... first off we don't have an air conditioner. We have a swamp cooler. Something that would make your life miserable in a VA summer (I grew up in coastal GA so I know how humid it is out there). The cooler uses about 20% the energy that an air conditioner would use. So we have a big advantage right there. Do you have a flat screen monitor? Replacing desktops with laptops (where practical) is another way to reduce consumption. We have a radiant range which we could swap out if we really wanted to. For us, the fridge would be our most effective replacement. Our next house will have solar water heating and PV. CO's got a rebate program that I'd like to take advantage of.

 

<div class='quotetop'>QUOTE(chogan @ Jan 4 2007, 09:54 AM) [snapback]370687[/snapback]</div>

Wow! You guys certainly give me something to shoot for! Here in South Florida, air conditioning represents the majority of my electric bill for the year. In 2005 I used a total of ~19,500 KwH. With a lot of small improvements, including the CFL's, my 2006 total was ~16,000 KwH, a reduction of about 17.5%. But, I think I'm well on track to see at least a 30% reduction this year, over my 2005 usage. The biggest energy savings I got was from a 2-speed pool pump. Anyone of you with a pool should look into this. They are mandatory in California, and I'd say it accounts for $30-$40 a month of my savings year round. The old pump was 1.5 HP. The new one is only ~1/4 HP on the low speed, where I keep it 99% of the time. I only use high speed when using the pool cleaner. I have to run it more hours per day, but it still pays big dividends! I found a company online that sells just the motor, for ~$289 if I recall, which paid for itself in 6-8 months.

 

Have anyone considered LED lamps, these are LED mounted into normal sized bulbs? I stumbled upon one on MythBusters and got intriuged, thought I saw they used only 10% of a CF!

Led should also be able to burn a VERY long time and be dimable so it seems like a great idea.

Been temped to buy one, but don't know a good source and what they cost.

 

<div class='quotetop'>QUOTE(keydiver @ Jan 5 2007, 04:46 PM) [snapback]371562[/snapback]</div>

Does FPL have an AC recirculation program? There's something that you can hook up to your AC and it will shutdown the compressor and just move the cool air around your house. If comes on a certain amount of the time and is automatic (ie, you just install it and it does the rest). eXcel Energy here in CO has a program like this. It's supposed to save a decent amount of electricity. We don't have an AC though, so I've never really looked into it. Since AC is such a large chunk of your bill you might wanna investigate.

 

We use CFLs in every socket where the bulb can't be seen.
Those curly lights are just sooooo ugly.

 

We have somewhere between 11-15 CFL's going right now with 10 more lined up for when more incandescents burn out. The local electric company subsidizes CFL's once a year at Home Depot: buy 2x 60-watt equivalent bulbs and get 2 more 60-watt equivalent and 2x 100-watt equivalent which is a great deal to me. Unfortunately, CFL's don't work that well in Manitoba winters. We have a few incandescents outside plus a 70-watt low pressure sodium lamp which is INTENSE, LPS is 2-3 times more efficient than a CFL bulb. It's pretty yellow but all we need is to see where things are so it works great.

 

<div class='quotetop'>QUOTE(lowlander @ Jan 3 2007, 11:27 PM) [snapback]370627[/snapback]</div>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

BOY - - You high-tech guys love to lord it over us peons! Just kidding -

I discovered that Walgren's carries 3 or 4 different LED night lights. They are pretty cool! And they hardly use any power.

 

I'm slightly irked. Last night, my CFL blew and it was only about 1 year old. What's up w/ this? I thought these things were supposed to last around a decade w/ normal use. The bulb had about 1,300 of use. Is it appropriate for a lady to say Wth??????

I use the bulb in a lamp that has a dimmer switch but I never touch the dimmer switch. I actually plug in the lamp when I need light and unplug it when done. Could this be the problem?

 

We use CFLs where possible, including over the stove and kitchen sink, front porch, rear CFL flood lights in back yard. You get equivalent light at 20% of the cost of a standard bulb.

When people complain CFLs are "not bright enough" I point out you can use four CFLs in the place of one standard bulb, get more light, still use less electricity and generate less heat.

 

<div class='quotetop'>QUOTE(SSimon @ Jan 24 2007, 04:27 PM) [snapback]380342[/snapback]</div>

Only true ladies drop F bombs. The rest are just posers.

I've had both types of bulbs die the first time I flipped the switch. Mfg defect perhaps. I don't know enough about dimmers to answer that part of it. What was the make on that bulb?

 

its not uncommon for a bulb rated at 20,000 hours to blow at 2,000. it happens. but at the same time, some will will go 50,000. moving it around, plugging it in and out is not good for it, especially if you have the light switched on when you plug it in.

obviously this will defeat the purpose of a CF, but if you were to leave one on 24/7, it would probably last 100,000 hours. the turning on and off is what wears them out.

 

<div class='quotetop'>QUOTE(tripp @ Jan 24 2007, 10:27 PM) [snapback]380406[/snapback]</div>

I can't remember for sure but I went back to the hardware store last night and they sell GE bulbs. I think it's safe to say that was the make upon my intial purchase. I'm a regular there and they gave me a bulb for free. I installed it last night and we'll see what happens.

The hardware manager told me that even though I plug in and out the cord, the dimmer switch on the cord may be inhibiting full current to the bulb even though the dimmer is fully "on". We'll see what happens now. You'll probably have to wait an entire year for my repost.

For the meanwhile, I'm content. I will now resume my female decorum.

<div class='quotetop'>QUOTE(DaveinOlyWA @ Jan 25 2007, 01:01 PM) [snapback]380622[/snapback]</div>

Makes good sense. It may be time to invest in a new lamp.

Oh, I almost forgot to mention. There is a CFL that is kinda like a flood lamp that can handle dimmer switches. I didn't opt for this as the wattage was not high enough for the intended purpose. He said they only carry one that is equpped like this. I thought this info may be useful to some.

 

<div class='quotetop'>QUOTE(SSimon @ Jan 25 2007, 10:33 AM) [snapback]380636[/snapback]</div>

Bombs AWWWWAAAAAAAAAAAAY!

That all makes sense. Just post daily reports on the new bulb's progress.

 

<div class='quotetop'>QUOTE(tripp @ Jan 25 2007, 01:36 PM) [snapback]380641[/snapback]</div>

k, I will retain a spread sheet.

 

<div class='quotetop'>QUOTE(SSimon @ Jan 24 2007, 07:27 PM) [snapback]380342[/snapback]</div>

Last time I looked at dimmers, the electronics only go from "most of the way off" to "most of the way on." Consequently, all have a mechanical override to turn them completely off and the few which had a mechanical override to "totally on" bragged about the feature. [Disclaimer: "last time" was about 15 years ago and I was looking at wall switch replacements.]

Simple test: take two identical incandescent light bulbs (make sure they are identical by putting both in lamps with no dimmer and verify they are both the same brightness). Now take one of the bulbs and put it in your dimmer lamp at max brightness. If you can see the difference in intensity, you don't need to wait a year to know your CFL will die early. Either replace the lamp or replace the dimmer with a mechanical switch (and then you don't have to wear out your outlets plugging it in and out either).

Technical test: Get one of your EE (that's electrical engineer, not elementary education) friends to check the waveform at the outlet under load to see how close to a sine wave the dimmer puts out. If it isn't pure, expect early death. If (s)he has a scope, expect to see the leading edge of each half cycle to stay at zero voltage for a bit before jumping up to where the sine wave value should be rather than passing smoothly through zero with no discontinuities.

Good luck and have fun, and read the instructions before replacing the dimmer with a switch...electrical wiring is easy and the rules are simple (at least for lamps and conventional outlets), but errors can kill you and/or burn your house down, so if in doubt, ask a professional.

Vince