Friday, January 11, 2008

Compact Fluorescents

Compact fluorescent lighting is a hot topic in the media right now. Repeated utility and environmental group campaigns have encouraged people to switch to them, and the Energy Independence and Security Act of 2007 will phase out the sale of incandescents in 2012. Economically speaking, there are real incentives for consumers to switch to them. But... people who have done so often come right back to incandescents. Why is that?

  • 1. Quantity of light. CF manufacturers are blatantly over-reporting the luminosity of the CFs. This will probably not be resolved until a lawsuit occurs over the false advertising. To get an equivalent amount of light I always recommend getting the CFL that is a step-up: so if you are replacing a 60W incandescent, buy a "75W" CF. You'll be much happier, and don't fret the increase in energy use, since you are still using less energy than before (60W vs 20W for a "75W" CF), it's still a win.

  • 2. Quality of light. This is the most legitimate complaint, and most of it stems from failure of manufacturers to label the color temperature of their bulbs. For most consumer applications, getting the color to match tungsten (2700K) is critical for acceptance. Some of the cheaper CFs have poor color rendition: they are too pink or too green and it turns off people. This is the fault of using the wrong phosphor blends. Take a gander at this quote from yesterday's NYTimes article on CFs:

    In the living room, for example, where there are four recessed lights along one wall, Mr. Chipman tested six dimmable bulbs and determined that one made by Greenlite with the same hue as incandescents worked best in certain spots, attractively lighting an exposed brick wall and maple bookshelves. A Satco brand bulb with a slightly whiter hue made a limestone-tiled fireplace in the middle of the wall look best, so he installed one above it. Mr. Chipman’s wife, Liz Diamond, 53, a theater director who considers herself even more particular about aesthetics than her husband, said investing time in trying multiple bulbs made a big difference. “There was one bulb that made the limestone look really freaky, ugly and moldy,” she said, but the Satco bulb now in place makes the space look “fabulous.” “I was amazed at how much variation there was, but you can really get a color that you like,” she said. Mr. Chipman agreed. “You really have to experiment with different bulbs to find the ones that work for you,” he said. “But they exist.”

    Get the right color for your application. I use GE 6500K daylight bulbs during the day to completely match outside light--you would be hard pressed to figure out if the light from the other room was from a window or the bulb. I also have some old tube "full-spectrum" fluorescents to wake up to in the morning in my bedroom. Again, these have fantastic matching color rendition to daylight.

    For nighttime, it's best to limit your exposure to blue light, as it disrupts the production of melatonin and hence your sleepiness. I switch to tungsten matching lights at night as much as possible. For matching incandescents, both the n:vision soft white and GE series match the color. The n:vision lights instantaneously, whereas the the GE takes too long to light (and has other objections below).

  • 3. Noise. A false objection is the claim that compact fluorescents buzz like old magnetic ballast fluorescent tubes. This is just wrong--CFs haven't used magnetic ballasts for a long time. Electronic ballasts, as used in CFs, can make noise if components in them aren't physically attached as well as they can be, and if certain cheaper circuits are used. The fundamental switching frequencies are ultrasonic, so you can't hear the old buzz that magnetics do. But with the design issues mentioned you can have a variety of whines and higher frequency buzzes.

  • 4. Time to light
    Many CF bulbs take a delay to light. This is annoying and a common complaint for many brands of bulbs. I've found that GE's Soft White 20W(75W) has a 1/2 second light time that drives me insane.

    In addition, every CF I've ever owned takes time to warm to full brightness. I don't mind a short delay. I've had no problem with the the warm-up time, but in hotels I've seen lights that have taken literally minutes to light up to full brightness.

  • 5. Short lifetimes
    A lot of people have reported the CFs aren't lasting as long as claimed. I can believe this, especially if they bought by price. The compact fluorescents also are very intolerant of cycling--don't use them in closets and places you don't need the lights on for hours at a time. The lights are also sensitive to overheating--so don't stick them in unventilated fixtures, or recessed ceiling cans, or in general any upside-down fixture.

    Now for long life. In 1991 or so I bought a very early CF. It was underpowered--I think it's a 7W. I used it for a few years and then went to college. It's still sitting in my old room at my parent's place, and I use it whenever I visit. Granted, this means it doesn't have many hours on it, but that CF bulb is older than many people I know.

    My own specific recommendations are to get N:Vision soft white CFs for general use. I can say they are as close to an incandescent as I've seen in CFs.

    I built an awesome "halogen torchiere killer" that I'll describe in another post.
  • No comments: