Saturday, February 2, 2008

CFL Experiences

[I am modifying the first paragraph of this post on 2/17/08 to say "up to 70" rather than "about 70" lumens per watt, to reflect the fact that 70 LPW is at the top end of the range of CFL performance. Also see this report on two tests of CFLs, which also confirms my personal experience of the amount of variation between CFLs, drop-off in brightness ovefr time, and failure rates.]

Like some political debate, conventional incandescent light bulbs produce more heat than light. In fact, only about 2% of the energy they use is emitted as light, which is why lighting is seen as “low hanging fruit” for energy conservation and why the US and other governments have legislated to phase these bulbs out. (Actually, the legislation does not ban incandescent bulbs explicitly, but mandates a minimum efficiency of about 20 lumens per watt. Current incandescents typically produce less than 15, while compact fluorescent lamps (CFLs) easily beat the proposed standard at up to 70 lumens per watt.) There are other alternatives, and in a later posting I hope to discuss the physics behind them, but today I am going to report my own experiences using CFLs and hope to get feedback. (In fact, I plan to concentrate my Saturday postings on the practical aspects of what individuals can do to reduce climate change.)

When I set out to write this, I had envisioned a rant about how bad CFLs were, but when I looked around the house I was surprised how many such bulbs I have and how unobtrusive most of them are. I did not count the bulbs, but I did count 10 different types from 5 brands. So, not all CFLs are created equal. There are however a few general points. Firstly, some people do not like the color of the light. It tends to be slightly bluer, though this “color temperature” varies from bulb to bulb. It is more like natural daylight, and I actually prefer it. Secondly, while they are meant to come on instantly, there is often a noticeable delay and/or a longer warm-up period during which they are relatively dim. Finally, some helicals are larger than conventional bulbs, and don't always fit into table lamps.

Most of the bulbs in the house come from Bright Effects, which I think belongs to Lowes. One is a regular 15W bulb (LBP16AM2) which is fine. Most are large 18W floodlights (LBP18R402) in can fixtures, and have also operated flawlessly so far (getting on for a year). However, I bought four smaller 15W floods (LPB15R30M2) which were mounted in more confining fixtures and which failed within 3 to 6 months. Lowes refused to replace them or refund the money, saying that they do not refund on light bubs. I think they need to rethink this policy for CFLs.

I have heard of other people with similar problems, and the problem may be that the bulbs do not work well when confined in can fixtures. Even CFLs produce quite a bit of heat, and the problem may be that the electronic ballast gets fried.

I also have four GreenLite dimmable floodlights, also mounted in can fixtures. So far none have failed, but one is temperamental. Sometimes it comes on for a second and goes off again and I have to “reboot” – switch off and wait a few seconds, or maybe play with the dimmer switch. I don’t dim them often, but I have found that they flicker when dimmed low. They are also among the worst for taking time to get up to full brightness.

Another interesting bulb is a 3-way bulb from Sylvania -- 12/19/29 watts which is equivalent to about 50/85/130 for an incandescent – and I have no complaints. I also have a dozen 9 watt Sylvania decorative globes in the bathroom which have worked flawlessly, with negligible delay in startup and close to full brightness immediately. I have one 19 watt helical Sylvania, however, which has a definite delay (maybe half a second of so) and also seems dimmer now than it was when I first installed it.

I also have a couple of GE helicals – 10W and 26W – which have been very satisfactory.

Finally, I have a 15W Lightwiz helical which was still in its box. I tried it out yesterday and it seemed to work well, but I have not tested it over time.

(I also have one very expensive LED light, which is very blue and so dim that if there is any other ambient light it is hard to see whether it is on or off without looking directly into it!)

All in all I think it is well worth making the switch to CFL, at least if you live in a hot climate; I live in Houston where we use A/C most of the year so producing less heat gives a double benefit and in my case it has contributed to a 25% drop in my electricity bills. (There is no real advantage at times when you are heating the space anyway, especially if heating with electricity.) The biggest problem seems to be failure of the ballast when confined in a can fixture, but some cans seem to provide more space than others. I should perhaps add the obvious fact that this is all highly unscientific and anecdotal. I welcome comments from others on their experiences with CFLs.

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