Compact Fluorescent Lamps

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  *                  COMPACT FLUORESCENT LIGHT BULBS                     *
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  *                       **** Version 1.10 ****                         *
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  *                      Copyright (C) 1996, 1999                        *
  *                        Samuel M. Goldwasser                          *
  *                        Donald L. Klipstein                           *
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What is a compact fluorescent lamp?
-----------------------------------

The compact fluorescent lamp is actually a fairly conventional, although
somewhat miniaturized fluorescent tube packaged with an integral ballast
(either iron ("magnetic") or electronic) in a standard screw base that can
be installed into nearly any table lamp or lighting fixture.

Some compact fluorescents are of the "modular" type, having bulbs and
ballasts that can be separated and replaced separately.  Others are of the
"integral" type, in which the ballast is permanently built into the bulb
and is discarded with the bulb when the bulb burns out.

These types are being heavily promoted as energy savings alternatives
to incandescent lamps.  They also have a much longer life - usually
7500-10,000 hours, sometimes up to 20,000 hours compared to 750 to 1000
hours for a standard incandescent.  While these basic premises are not in
dispute - all is not peaches and cream:

1.  They are often physically larger than the incandescent bulbs they replace
    and simply may not fit the lamp or fixture conveniently or at all.

2.  The funny elongated or circular shape may result in a less optimal
    lighting pattern.

3.  Many models have light output claims that are only achieved at the
    optimum operating temperature and/or in some optimum burning position
    that achieves an optimum internal temperature.  Many light output
    claims are outright exaggerated, often by about 15 percent and in a
    few extreme cases by 25 percent.

4.  Compact fluorescent lamps usually do not produce full light output
    until they warm up for a minute or two.  A few models require about
    three minutes to fully warm up and produce as little as 20-25 percent
    of their full light output when first started.

5.  The light is usually slightly different from that of incandescents,
    often slightly less yellow and slightly more pink, more purple, or
    more blue. The spectral output of these lamps is usually concentrated
    in a few specific bands of the spectrum, and this can slightly distort
    color rendering.
    Any color difference from other nearby lamps may be undesirable and
    result in less than pleasing contrast with ordinary lamps and ceiling
    fixtures.  Newer models have been addressing this issue.

6.  Some types (usually iron ballasts) may produce an annoying 120 Hz
    (or 100 Hz) flicker.

7.  Ordinary dimmers cannot be used with compact fluorescents.

8.  Like other fluorescents, operation at cold temperatures (under around
    50 degrees F) may cause reduced light output or erratic operation.
    Some models work fairly well down to about 35 degrees F, others may
    get noticeably dim below 60 degrees F.  The optimum temperature range
    of a particular lamp may vary with burning position, generally
    preferring cooler temperatures if operated base-down.
    Compact fluorescents may also not like excessive heat.  Some ballasts
    are unreliable in ambient temperatures much over 120 degrees F.  This
    is sometimes a problem in enclosed or recessed ceiling fixtures if
    heat in the fixture builds up.

9.  There may be am audible buzz from the ballast, usually from iron
    ballasts.

10.  They may produce Radio Frequency Interference (RFI).

11.  The up-front cost is substantial (unless there is a large rebate): $10
    to $20 for a compact fluorescent to replace a 60 W incandescent bulb!

12. Due to the high up-front cost, the pay-back period may approach infinity.

13. While their life may be 20,000 hours, a wayward baseball will break
    one of these $10 to $20 bulbs as easily as a 25 cent incandescent.

14. Few commonly available compact fluorescent lamps designed to fit
    into 120 volt ordinary light bulb sockets match or exceed the
    light output of a 100 watt standard incandescent lamp.  One not-so-
    compact "circline" unit designed to fit into table lamps is about as
    bright as a 100 watt bulb, or slightly brighter, but is claimed
    to be as bright as a 150 watt bulb.
    A 28 watt General Electric model matches "100 watt" brightness, but
    has above-average RFI emissions.  Lights of America produces a 34 watt
    model that slightly outshines a 100 watt lightbulb and a 45 watt model
    that is almost as bright as a 150 watt lightbulb.  Beware of higher
    claims on the packages that are met only in specific (probably
    unusual) conditions - if at all.

15. Like other fluorescent lamps, compact fluorescent lamps should only
    be used where they are left on (on an average) at least 15 minutes,
    preferably at least a half hour, once they are turned on.  Starting
    a fluorescent lamp causes wear and tear on the electrodes (except for
    a few specific exceptions such as RF electrodeless lamps).

Nonetheless, due to the lower energy use and cooler operation, compact
fluorescents do represent a desirable alternative to incandescents.  Just
don't open that investment account for all your increased savings just yet!


  -- end V. 1.10 --