[SustainableTompkins] How Many Lightbulbs Does it Take to Change the World?

[bosak at ibiblio.org]

The article on compact fluorescent lightbulbs (CFLs) brings to
mind a couple of questions I've been wondering about for quite a
while.

My wife and I switched to CFLs (the new spiral kind, not the old
style) about four years ago, replacing just about every tungsten
bulb in the house with a CFL.  We did indeed save a lot of
electricity, but we also found that CFLs (yes, the new ones) don't
last anywhere near as long as claimed.  In actual service, we're
lucky to get a couple of years out of them; the statement in the
article that "compact fluorescents, even in heavy use, last 5, 7,
10 years" simply isn't true as far as I can tell.

It's also not true that "compact fluorescents emit the same light
as classic incandescents." Like all fluorescents, CFLs don't put
out a complete spectrum; they put out a couple of sharp spikes at
certain wavelengths, the combination of which is carefully
engineered to give an impression of (more or less) white light
that works OK until you try to judge color combinations of
clothing or makeup or artwork, at which point the missing
wavelengths make accurate assessments almost impossible.
Incandescent bulbs, while having a color temperature much warmer
than daylight (2700-3200 degrees Kelvin vs. 5000-5500 for
daylight), do put out a continuous spectrum, which is why you'll
always see incandescents used at makeup tables and in museums.
(Some people believe that the discontinuous spectral output of
fluorescents is actually bad for you, but I haven't noticed any
deleterious effects from using them at night.  Working all day in
a room lit by nothing but CFLs, with no supplementary window
light, might be a different matter.)

Another claim for CFLs that isn't true is that they "use 75% or
80% less electricity."  If this were so, a CFL that used 15 watts
would give off as much light as a tungsten bulb that used four to
five times as much, that is, 60 to 75 watts.  In reality, CFLs
give off as much usable light as a bulb rated about three times as
much, not four or five.  (Yeah, I know that the measured lumens
from a 15 watt CFL are the same as from a 60 watt incandescent.
Try working in a room lit by one and then the other and see for
yourself.  I think that the people who are happy substituting a 15
watt CFL for a 60 watt incandescent have just discovered that they
can get by with a little less light than they thought they could
-- which is an important and useful discovery to make, but not
what's being claimed.)  I read somewhere a couple of years ago of
a proposal to require ads for CFLs to use the factor of three
rather than the factor of four that you always see on packages,
but this seems not to have gone anywhere.

None of this is to question the advisability of replacing
incandescents with CFLs wherever appropriate; the question is,
what are the appropriate uses for them?  And this leads me back to
the longevity issue.  My suspicion is that the longevity of CFLs
is directly related to how often they are switched on and off.  A
CFL that can easily deliver its rated life of 10,000 hours if left
on continuously is unlikely to survive 60,000 duty cycles of 10
minutes each.  (This is true of most electrical devices.)  So my
first question to this group is: Has anyone produced guidelines
for the breakeven point between fluorescent and incandescent bulbs
depending on how long they are left on each time?  My hunch is
that the light in a closet that's rarely on longer than a minute
at a time is properly served by an incandescent, whereas the light
in an office that's left on for hours at a time is properly served
by a fluorescent, but where's the dividing line?

My second question is a larger one.  Has anyone done a *complete*
energy accounting comparison of fluorescents vs. incandescents --
one that includes not just the energy used to run CFLs, but also
the energy used to produce the raw ingredients, manufacture them
(taking into account the environmental costs of the exotic
materials used to produce the electronic components), transport
them all the way from China (which is taken as a given in the
dollar cost comparisons), and finally dispose of them (including
dealing properly with the poisonous materials they contain)?

Around our house, we'll no doubt dutifully continue to use CFLs
where there's even a chance that they make sense, but without a
complete energy accounting, I'll continue to wonder whether we're
not just externalizing some essential input, like the folks who
believe that ethanol from corn represents a net energy gain.

Jon