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Cool light from very cheap energy saving bulbs

Discussion in 'Lighting' started by David Peters, Mar 16, 2006.

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  1. David Peters

    David Peters Guest

    My local discount store sells energy saving bulbs at a very cheap

    I mean the type of lamp made up of small folded fluorescent tube
    which plugs into a standard light socket.

    There is no color temp written on the discount bulbs but I notice
    their light is very noticably cooler than some similar GEC bulbs I
    have. They are rated at 9 W, 11 W, 20 W.

    Is the color temp of these lamps pure a matter of choice or are there
    some technical, financial or marketing reasons which determine why
    the lamps give off such a cool light?
  2. I don't know, maybe cooler colors are cheaper to produce. I have
    purchased $1 CFLs that produce a daylight color. One brand I bought was
    good, the other brand failed anywhere between 2 minutes and 40 hours.

  3. In warmer climates a cool white is preferred and in cool climates a warm
    white is preferred. I think the biggest market for CFL's is for the
    warmer climates so they use the cool white phosphors.

    It's interesting that some of the cheap lamps have very good colour
    rendering indexes. (CRI's) It would be nice to see a side by side
    comparison with a "full spectrum" lamp.

    Some attempts at warm white are woeful and give off a lurid fleshy

    If you end up with any dead CFL's then remember that the little torroid
    feedback transformer inside is ideal for making Joule Thief type
    circuits that drive a white LED from a 1.5V cell. All you need to add
    is a 1k resistor, a common NPN transistor and some fine enamelled wire.
    Just thought I'd mention it.... You can find the Joule Thief on my
    website below.
  4. It's mostly a matter of choice, and has been said, there are
    regional differences in color temperature preferences. Note
    that at a given CCT, the color quality, CRI, is a matter of

    Vic Roberts
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  5. I have tested a lot of dollar store CFLs. Most are "daylight" color to
    slightly more blue. The phosphor is usually the cheaper halophosphor
    general type.
    One thing I have found fairly consistently of $1 and $1.50 CFLs from
    dollar stores: They produce less light than claimed, and generally by a
    larger extent (sometimes by a factor of 3) when the claimed output is

    - Don Klipstein ()
  6. Adam Funk

    Adam Funk Guest

    IMHO (and this is based on subjective evaluation with my eyes, not
    measuring with instruments) *all* CFLs are less effective than the
    equivalent incandescent wattages printed on the packaging.

    I like CFLs anyway, because they save energy and last much longer. I
    just replace 60W incandescent lamps with "100W equivalent" CFLs, for
  7. By "smaller by a factor of 3" do you mean 1/3 the claimed
    output? Is this a measured value? I've seen low output
    lamps but ever as low as 1/3 the claimed output - but then
    again I don't do my lighting research in dollar stores :)

    Vic Roberts
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.

    This information is provided for educational purposes only.
    It may not be used in any publication or posted on any Web
    site without written permission.
  8. I agree that some of the "equivalent wattage" statements are
    too high. You should be comparing the output in lumens for
    the various lamp types. Even then, the subjective
    evaluation of some people is that CFLs don't produce as much
    light as an incandescent lamp with the same lumen output.
    Other than differences in light distribution, I don't have a
    good explanation for this. Perhaps Terry has additional

    Vic Roberts
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.

    This information is provided for educational purposes only.
    It may not be used in any publication or posted on any Web
    site without written permission.
  9. It is my impression that this is a large factor in people
    deciding not to use CFLs. An answer I've heard many times
    when asked why not use a CFL is that they bought one with
    the equivalent power to the existing filament lamp, and it
    was far too dim. That became their first and last experience
    with CFLs.

    One factor may be the poor cool starting light output, and
    without any realisation that the thing will get brighter in
    a minute or so -- it might not even get a minute or so to prove
    itself before it's been removed. Another factor I've heard
    is that the light comparison can be with things like soft-
    tone lamps which for the most part aren't what people use.

    My rule of thumb is to multiply the power by no more than
    4 times to get the equivalent filament power, and ignore
    the filament power equivalent written on the box. For 120V
    filament lamps (as opposed to 240V ones here), the factor
    might want to be less than 4. The actual factors used on
    the lamp cartons is always greater than 4 times -- usually
    5 times.
  10. I tend to replace a 100W lamp with 100W's worth of CFL's, and that
    doesn't include the shit power factor, so I probably end up using more

    The new UK building regulations seem to be resulting in the installation
    of pendant lampholders with an integral electronic ballast that can only
    take the bare compact fluorescent lamps. Accordingly their price can be
    anything the suppliers like.

    Such a bad idea wiring an electronic ballast in directly to the
    permanent wiring. Most householders will not be comfortable
    disconnecting the dead ballast from the ceiling rose themselves.
    (Assuming they're even allowed to with the part P nonsense.) Somebody's
    going to be making lots of money.
  11. Yep -- that's under Part L of building regs (conservation of energy
    and power). A certain proportion of commonly used rooms in a house
    must be lit with luminares with an efficiency of 40lm/W or better,
    which must not be able to take lower efficiency lamps.

    I don't object at all to encouraging use of more efficient
    lighting. But as always, it's been gone about the wrong way.
    Apparently, electricians often have a handful of these that they
    lend out whilst the building inspector does the final check, and
    then they recover for use in the next job.

    The choice of available compact fluorescent luminares for the home
    market that are even vaguely acceptable in the home is vanishingly
    small. Pretty much all my home lighting is compact fluorescent (with
    a mixture of self ballasted and remote ballasted lamps), but it is
    nearly all made by me, as I can't find any aesthetically pleasing
    luminares to use.
  12. Yeah, but have you made one of my sputnik lights yet? :)

    I'm lighting the room with it as I type. It's been tamed down though,
    the top lamp holders are fitted with flicker flame neon lamps.
  13. I don't have anything better than a Bunsen photometer and plenty of "Big
    3" incandescents to compare against. And a few voltmeters and a "variac"
    to supply exactly 120V to incandescents with. And I know how a quadtube
    has different light distribution from "soft white" and close to but
    slightly different from a bare CC-8 or CC-6 filament aligned in the same
    direction. And that determining lumens this way gets "fudgier" when one
    lamp has CCT below 3,000 K and the other has CCT in the 6500-8000K range!

    But I have yet to see a $.99-$1.50 "dollar store CFL" impress me as
    outshining the brightest 40 watt A19 lamps that come in packages claiming
    505 lumens - none of 42 "models" of 16 "brands" that I tried! This
    includes some that claim to replace 100 watt incandescents, a few claiming
    to replace 125 watt incandescents, and a few claiming to replace 150 watt
    incandescents. This includes two claiming to produce 1130 lumens and one
    claiming to produce 1580 lumens! Most avoid lumen statements, even most
    with claims of "incandescent equivalence" or "incandescent replacement" or
    the like.

    1580 or 1130 lumens from something that I see as slightly dimmer than a
    40 watt A19? GRADE ZZZ-minus BULL COOKIES!!!

    - Don Klipstein ()
  14. David Peters

    David Peters Guest

    This shows a very neat resin job on the bulb on the left.
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