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Posted by m Ransley on February 18, 2004, 6:06 pm
 
Am  I correct in that  an incandesant light outputs 17 Lumen Per Watt
and only produces a small amount of light per watt. Ex a 100 watt bulb
produces 10 watts light , 90 watts heat, effectively making it a heater
that produces light.
 A T-8 flouresent  can produce near 110 LPW  , 6.5 x an incandesant.
Making  T- 8 the most efficient  home lighting.
 Is 170 LPW  the limit of light  output per watt.
 Is T-8 the most efficient,
  What can the near future  offer us in LPW increases.  
 Are my  figures correct


Posted by Mark or Sue on February 19, 2004, 4:55 am
 


Sort of. The light produced by an incandescent source is non linear. The larger
the lamp (in watts),
the higher the lumens per watt. The little 25W and 40W lamps are pathetic for
efficiency, whereas
the 200W and 300W lamps are much better. But they are still in the 5 to 15
lumens per watt range.
Halogen versions improve on this somewhat.

There are some new LED based lamps with edison bases that are another small step
up in efficiency.
They also produce more usable lumens because of the nature of the light source.
But I've never seen
them to know what their light quality is like. If its like the LED flashlights,
they could be hard
on the eyes. The future may be here for a direct incandescent replacements.

Fluorescents are a huge jump in efficiency. Now that they have decent color
temperatures and good
CRI's, they aren't a bad source of lighting at all (about 5X that of
incandescents).

There are even more efficient light sources (metal halide I believe), but they
all seem to have a
long warm up time so their uses are limited.

No matter which light source you choose, just about all the power will be
dissipated as heat. In the
fluorescent, a twin 32w fixture will dissipate about 64 watts between the
ballast and the lamps. No
way around this for just about anything electrical.

--
Mark
Kent, WA




Posted by Stuart Brown on March 1, 2004, 2:40 am
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Compact Fluorescent Lights seem to be doing a pretty good job of eating
into the incandescent market.. 18W for the same lighting value of a 60
Incandescent. bulb.  We have bought a few in the house to test how long
they last and to see if it is actually worth paying the $ CDN for a
bulb instead of 8 or 10 bulbs at $.60 ea.

Stu Brown
Saskatoon SK




Mark or Sue wrote:


the lamp (in watts),

efficiency, whereas

lumens per watt range.

step up in efficiency.

But I've never seen

they could be hard

temperatures and good

incandescents).

all seem to have a

dissipated as heat. In the

ballast and the lamps. No

--------------060503010705040109070008
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Content-Transfer-Encoding: 7bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1">
  <title></title>
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<body text="#000000" bgcolor="#ffffff">
Compact Fluorescent Lights seem to be doing a pretty good job of eating
into the incandescent market.. 18W for the same lighting value of a 60
Incandescent. bulb.&nbsp; We have bought a few in the house to test how long
they last and to see if it is actually worth paying the $ CDN for a
bulb instead of 8 or 10 bulbs at $.60 ea.<br>
<br>
Stu Brown <br>
Saskatoon SK<br>
<br>
<br>
<br>
<br>
Mark or Sue wrote:<br>
  <pre wrap="">"m Ransley" <a class="moz-txt-link-rfc2396E"
<a class="moz-txt-link-freetext"
  </pre>
  <blockquote type="cite">
    <pre wrap="">Am  I correct in that  an incandesant light outputs 17 Lumen
Per Watt
and only produces a small amount of light per watt. Ex a 100 watt bulb
produces 10 watts light , 90 watts heat, effectively making it a heater
that produces light.
 A T-8 flouresent  can produce near 110 LPW  , 6.5 x an incandesant.
Making  T- 8 the most efficient  home lighting.
 Is 170 LPW  the limit of light  output per watt.
 Is T-8 the most efficient,
  What can the near future  offer us in LPW increases.
 Are my  figures correct
    </pre>
  </blockquote>
  <pre wrap=""><!---->
Sort of. The light produced by an incandescent source is non linear. The larger
the lamp (in watts),
the higher the lumens per watt. The little 25W and 40W lamps are pathetic for
efficiency, whereas
the 200W and 300W lamps are much better. But they are still in the 5 to 15
lumens per watt range.
Halogen versions improve on this somewhat.

There are some new LED based lamps with edison bases that are another small step
up in efficiency.
They also produce more usable lumens because of the nature of the light source.
But I've never seen
them to know what their light quality is like. If its like the LED flashlights,
they could be hard
on the eyes. The future may be here for a direct incandescent replacements.

Fluorescents are a huge jump in efficiency. Now that they have decent color
temperatures and good
CRI's, they aren't a bad source of lighting at all (about 5X that of
incandescents).

There are even more efficient light sources (metal halide I believe), but they
all seem to have a
long warm up time so their uses are limited.

No matter which light source you choose, just about all the power will be
dissipated as heat. In the
fluorescent, a twin 32w fixture will dissipate about 64 watts between the
ballast and the lamps. No
way around this for just about anything electrical.

--
Mark
Kent, WA



  </pre>
</blockquote>
</body>
</html>

--------------060503010705040109070008--


Posted by Dale Farmer on March 1, 2004, 3:16 am
 

Stuart Brown wrote:


    IN a lot of places, the local power company is subsidizing the cost
of
the bulbs in local stores.  Here in Massachusetts, one of the local
discount
stores has bins full of CF bulbs for one dollar each.  Limited
selection, but
can't beat the price.

    --Dale



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