This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a foul-smelling
compound which he named cacodyl oxide and a whole series of related compounds
which turned out to be highly explosive. At one point, Bunsen accidentally
blew up his lab and was laid up in bed for a long time.

The grease spot disappeared (indicating equal illumination on both sides) when
the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
= 1.27 times the CF light output. After a minute or so, the 100 watt bulb
consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
lumens per watt.

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.

Nick

Nice experiment! Thanks.

wrote:
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a foul-smelling
compound which he named cacodyl oxide and a whole series of related compounds
which turned out to be highly explosive. At one point, Bunsen accidentally
blew up his lab and was laid up in bed for a long time.

The grease spot disappeared (indicating equal illumination on both sides) when
the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
= 1.27 times the CF light output. After a minute or so, the 100 watt bulb
consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
lumens per watt.

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.

Nick

wrote:
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W
equivalent" 23 W 10,000-hour Commercial Electric compact fluorescent
with a 9-year guarantee ($8.97 for 4 from Home Depot) and compared
the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white
paper :-)

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was
known as
an inept experimentalist with radical theories who isolated a
foul-smelling compound which he named cacodyl oxide and a whole
series of related compounds which turned out to be highly explosive.
At one point, Bunsen accidentally blew up his lab and was laid up in
bed for a long time.

The grease spot disappeared (indicating equal illumination on both
sides) when the paper was 42.4 cm from the incandescent bulb, so it
had (42.4/(80-42.4))^2 = 1.27 times the CF light output. After a
minute or so, the 100 watt bulb consumption dropped from 100 to 99
watts and the CF rose from 22 to 24, so the CF was 99/(1.27x24) =
3.24 times more efficient, with 3.24 times more lumens per watt.

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot)
used 35 watts and made the spot disappear 36.2 cm from the 100 W bulb
when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.

Nick

Good Job.

--
Joseph Meehan

Dia duit

wrote:

This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a foul-smelling
compound which he named cacodyl oxide and a whole series of related compounds
which turned out to be highly explosive. At one point, Bunsen accidentally
blew up his lab and was laid up in bed for a long time.

The grease spot disappeared (indicating equal illumination on both sides) when
the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
= 1.27 times the CF light output. After a minute or so, the 100 watt bulb
consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
lumens per watt.

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.

Nick

Nick, this is much more useful than a lot of your pie in the sky
calculations. Well done.

BTW, if the CFs were in a pack of four, did you test for variations?
That would be useful information as well.

Also, did you check the lumen output either by using a standard
candle, or a photometer (perhaps one in a camera?). Incandescent
lamps dim with age, so using an older 100 watt lamp might have
affected the results.

wrote in message
...
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper
:-)

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a
foul-smelling
compound which he named cacodyl oxide and a whole series of related
compounds
which turned out to be highly explosive. At one point, Bunsen accidentally
blew up his lab and was laid up in bed for a long time.

He might have been inept but his name has lasted longer than many who were
ept :-)

How many of his critics' inventions are still used?

Mary

wrote:

This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)

the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
lumens per watt.

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot)
[...]
was 98/(0.683x35) = 4.10 times more efficient.

Many Thanks!

How did you measure 42.4cm from the bulb, or is that like R 3 aluminum
foil..........

m Ransley wrote:

How did you measure 42.4cm from the bulb...

I lined up the center of each bulb on the 0 and 80 cm marks on
a Craftsman 939675 8m/26' measuring tape, then moved the paper
along the tape until the grease spot disappeared at 42.4 cm.

Nick

Harry Chickpea wrote:

wrote:

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a
foul-smelling compound which he named cacodyl oxide and a whole series of
related compounds which turned out to be highly explosive. At one point,
Bunsen accidentally blew up his lab and was laid up in bed for a long
time.

This part may not have been vital - but it's the sort of thing I love to
know :-)

so the [23W] CF was 99/(1.27x24) = 3.24 times more efficient,
with 3.24 times more lumens per watt.

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.

Nick, this is much more useful than a lot of your pie in the sky
calculations. Well done.

I'm sure many of his calculations are useful to people who want to be
frugal - but I'm stunned that Nick managed this without a line of Basic
code :-)

The numbers are interesting - the 23W CF really was approximately 23W but
the 42W CF was much less. I'm not at all surprised that the 23W bulbs
really aren't 100W-equivalent - typical marketing hype - but those results
are acceptable to me.

Also, did you check the lumen output either by using a standard
candle, or a photometer (perhaps one in a camera?). Incandescent
lamps dim with age, so using an older 100 watt lamp might have
affected the results.

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek

In Derek Broughton writes:
[ various snippages ]

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.

Also, did you check the lumen output either by using a standard
candle, or a photometer (perhaps one in a camera?). Incandescent
lamps dim with age, so using an older 100 watt lamp might have
affected the results.

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?

- also, keep in mind that the lumen ratings for
traditional fluorescents are the initial output,
but... it's _after_ 100 hours of burn in.

When first lit, they tend to be a modest amount
brighter than spec. There's a rapid 'burn off" (for
want of a better description, and then, at a nominal 100 hrs,
they stabilize (to a slight long term downward slope).

So if you used brand new CFLs, you're seeing a bit
of an artificial peaking...


--
__________________________________________________ ___
Knowledge may be power, but communications is the key

[to foil spammers, my address has been double rot-13 encoded]

Derek Broughton wrote:

... the 23W CF really was approximately 23W but the 42W CF was much less.

Surprising...

... did you check the lumen output either by using a standard candle,
or a photometer (perhaps one in a camera?).

No. I'm not sure how standard standard candles are.
I've used CSA standard fingers...

Don't CFs dim with age?

I believe they do.

Can we then expect the relative efficiency to improve over time?

I doubt that. Don Klipstein might help here.

Nick

Can we then expect the relative efficiency to improve over time?


I doubt that. Don Klipstein might help here.

Nick


I think they dim cause the mercury sticks somewhere or soemthing, but no
current drop I would think

wrote:
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a foul-smelling
compound which he named cacodyl oxide and a whole series of related compounds
which turned out to be highly explosive. At one point, Bunsen accidentally
blew up his lab and was laid up in bed for a long time.

The grease spot disappeared (indicating equal illumination on both sides) when
the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
= 1.27 times the CF light output. After a minute or so, the 100 watt bulb
consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
lumens per watt.

After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.

Nick
//

Tut writes:

Nick, if you replace one of the lamps with a burning candle, you can
calculate the strength of the each lamp in candles vs lamp wattage.

E=C/d^2-------- C1/d1^2=C2/d2^2

whe E=foot-candles
C1= one candle
C2= candles of light source
d1= distance to oil drop for burning candle
d2= distance to oil drop of lamp under test

In article ,
says...
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)

Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a foul-smelling
compound which he named cacodyl oxide and a whole series of related compounds
which turned out to be highly explosive. At one point, Bunsen accidentally
blew up his lab and was laid up in bed for a long time.

The grease spot disappeared (indicating equal illumination on both sides)


I almost read that as meaning "the grease spot" that was left on
the floor where Robert Bunsen was standing at the moment of the
lab explosion.


--
Want Freebies?
http://www.TheFreeStuffList.com/
Check The Free Stuff List

wrote in message ...
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)

Yeah, I've got some of those 100W equivalent, $8.97 bulbs, with a 9-year
guarantee too.

I don't need a grease-spot photometer to tell me they don't put out as
much light as a 100W bulb. My own eyes can tell me that. It takes a
150W equivalent to be a 100W equivalent, IMO.

The one in the hallway went out after about a year and a half to two
years. I don't know where my receipt is, so I guess I'm out a few bucks.

These CFL's sure are frugal. Just make sure you send in any rebates
and keep track of your receipts and the packing material for the
next 9 years.

Don

Don K wrote:

Yeah, I've got some of those 100W equivalent, $8.97 bulbs, with a 9-year
guarantee too.

I don't need a grease-spot photometer to tell me they don't put out as
much light as a 100W bulb...

It worked out to 79%, but still an energy bargain.

The one in the hallway went out after about a year and a half to two
years. I don't know where my receipt is, so I guess I'm out a few bucks.

Maybe not. These bulbs have a phone number (800) 378-6998 and a date code
V# xxxxx printed on the base. I called the number and gave them the code
and they sent me a new one, after one died.

Nick

"Don K" wrote in message
. ..
wrote in message
...
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper
:-)

Yeah, I've got some of those 100W equivalent, $8.97 bulbs, with a 9-year
guarantee too.

I don't need a grease-spot photometer to tell me they don't put out as
much light as a 100W bulb. My own eyes can tell me that. It takes a
150W equivalent to be a 100W equivalent, IMO.

I think that too.

The one in the hallway went out after about a year and a half to two
years. I don't know where my receipt is, so I guess I'm out a few bucks.

These CFL's sure are frugal. Just make sure you send in any rebates
and keep track of your receipts and the packing material for the
next 9 years.

We pencil the installed date and the supplier on the item itself. We've only
twice had to return them and they've been replaced with no receipt and no
question.

Customer goodwill is important to stores. The items are cheap and it's
recognised that some will fail.

Mary

In article ,
Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek

No, not typically. Very few Gas Discharge lights dim with age unless
the excitation voltage drops significantly. The Gas doesn't wear out,
but the electronics that fire the voltage may.....

No, again not typically. Very few electronic systems get better as
the components age, so efficency should slowly drop a bit with age....

You wrote:

Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?

No, not typically. Very few Gas Discharge lights dim with age...

IIRC, most do.

Nick

wrote in message
...
You wrote:

Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?

No, not typically. Very few Gas Discharge lights dim with age...

IIRC, most do.

In my experience they do.

Mary

"You" wrote in message
...
In article ,
Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek

No, not typically. Very few Gas Discharge lights dim with age unless
the excitation voltage drops significantly. The Gas doesn't wear out,
but the electronics that fire the voltage may.....


snip

They why does my employer change out the fluorescent lighting about every 5
or 6 years even when they are all burning good? When they do, the rooms are
so much brighter. Makes a huge difference.




---
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You wrote:
In article ,
Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek

No, not typically. Very few Gas Discharge lights dim with age unless
the excitation voltage drops significantly. The Gas doesn't wear out,
but the electronics that fire the voltage may.....

No, again not typically. Very few electronic systems get better as
the components age, so efficency should slowly drop a bit with age....

ALL lighting dims with use! It is called "Lamp Lumen Depreciation"
(LLD) by the pros and can be found in the detailed specifications from
the manufacturers.
Mostly in fluorescents the electrode loses some tungsten (those black
ends, just like incandescents) and there is some mercury loss as well.
Both degrade the starting and the arc, THAT causes less light.

Electronics is a whole other issue. As is dirt on the bulb and fixture.

It is useful to note that LLD is not related to when a lamp fails. This
is why some folks claim bulbs that have lasted extreme times, the
efficiency has gone to ****.

Other things to note:
1. All lamps should have a "lumen" rating on the package. This is the
actual amount of light as measured by more advanced technology than
eyeballing a dirty piece of paper.. It should also have the expected
life, in hours. Multiply the two. This is how much light you are buying
for the price of the bulb and the power.

Formula is as follows:
(Lumens (adjusted for LLD if you want get detailed) x Life) / (Watts x
Life x $) = true efficiency (lumens per dollar).
Note that you have to get your units right. Power is usually sold in
KWH = 1000 watts for one hour or one watt for 1000 hours. Also the lamp
life is an average statistic so it applies over large numbers of bulbs.
;-)

2. There are many kinds of incandescent bulbs. Soft White - IF - Clear
- colored - 130V -120V - "long life" - halogen - shatter resistant -
vibration resistant.... ALL have different light output.

3. CF's come in even more types and will vary widely by brand, model,
color, lot and even within a lot.

4. Heat, especially inside a fixture, can dramatically change a
fluorescent lamps efficiency. (Both too much and too little are
problems.) This is why CF's upside down in recessed fixtures tend to
fail quickly.

5. CF's are a softer, more diffuse light that will not be reflected
inside a fixture the same way as an incandescent will.

Richard Reid, LC
Luminous Views
Lighting Design for Home and Business

Derek Broughton wrote:
Don't CFs dim with age?

Yes, they do, in fact their lifetime is based not on loss of
functionality, but on reaching some percentage of nominal output.

Can we then expect the relative efficiency to
improve over time?

No, that would make relative efficiency _drop_ over time.

RickR wrote:

... All lamps should have a "lumen" rating on the package. This is the
actual amount of light as measured by more advanced technology than
eyeballing a dirty piece of paper.

But perhaps no more accurately. I've seen Bunsen photometers in modern
physics labs, mounted on optical benches, and so on.

Nick

"Bob Adkins" wrote in message
...
On Sat, 15 Jul 2006 21:34:46 GMT, "C. Massey" wrote:


They why does my employer change out the fluorescent lighting about every
5
or 6 years even when they are all burning good? When they do, the rooms
are
so much brighter. Makes a huge difference.

I'm betting the replacement was wasted. That's because the lamps were
changes individually as they failed. In other words, the average age of
the
tubes they were changing out was far less than 5 years!

No, that is the reason to change out all the bulbs. At home we usually
change a bulb when it is gone. No big deal. In a factory or large office,
getting the lifts, scaffolding or whatever together, two employees +
overhead costs, they often find it cheaper just to sweep through an area and
change 100% of the bulbs at one time. That way, there are few, if any,
changes between, thus the average is still very high at 5 years.

If one bulb goes, all the others at that age are probably not far behind.
At work, we don't change the entire plant, but will do a section at a time.
When you have 20' ceilings, it is cheaper to change what you can get at once
the equipment is in place.

On Sun, 16 Jul 2006 08:44:09 -0500, Bob Adkins
wrote:

On 14 Jul 2006 08:40:24 -0400, wrote:

This morning I put two $20 Kill-a-Watt meters on two power strips with
Nick,

Excellent experiment.

Have you ever done a long term cost analysis on CF vs. incandescent? Does
the increased cost and short life of CF's negate the improved efficiency?

What short lives? I've been writing the install date on my CFs from
the beginning and have been keeping a log. Average life is about 4.5
years. The best one, a low wattage lamp in my bathroom that burns
24/7 is still going at 9+ years.

When I can buy a pack of 5 from Sam's for $9, only a bit more than an
equivalent incandescent, the enconomics become a no-brainer.

John
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
Don't let your schooling interfere with your education-Mark Twain

"Edwin Pawlowski" wrote in message
...

"Bob Adkins" wrote in message
...
On Sat, 15 Jul 2006 21:34:46 GMT, "C. Massey" wrote:


They why does my employer change out the fluorescent lighting about every
5
or 6 years even when they are all burning good? When they do, the rooms
are
so much brighter. Makes a huge difference.

I'm betting the replacement was wasted. That's because the lamps were
changes individually as they failed. In other words, the average age of
the
tubes they were changing out was far less than 5 years!

No, that is the reason to change out all the bulbs. At home we usually
change a bulb when it is gone. No big deal. In a factory or large
office, getting the lifts, scaffolding or whatever together, two employees
+ overhead costs, they often find it cheaper just to sweep through an area
and change 100% of the bulbs at one time. That way, there are few, if
any, changes between, thus the average is still very high at 5 years.

If one bulb goes, all the others at that age are probably not far behind.
At work, we don't change the entire plant, but will do a section at a
time. When you have 20' ceilings, it is cheaper to change what you can get
at once the equipment is in place.

Agreed. The use of 'group relamping' (replacing all bulbs at once even
though many are still burning) has some advantages even though some bulbs
are replaced prematurely. Since bulb life is pretty predictable, most of
the replacements will not burn out too soon. All the bulbs are from the
same stock (usually), so it avoids mixing up different 'colors' such as
'cool white', 'softwhite' and 'daylight' in an area. And as you mentioned,
the 'overhead' of getting crew, tools, and equipment scheduled. If 'group
relamping' is done on a performance basis (for example, whenever 10% of the
bulbs have burned out), then large areas of burned out bulbs are usually
avoided.

'Spot relamping' has the advantage that maximum use of each bulb is attained
and only a small quantity of replacements are needed to keep on hand at any
one time.

daestrom

wrote in message
...
RickR wrote:

... All lamps should have a "lumen" rating on the package. This is the
actual amount of light as measured by more advanced technology than
eyeballing a dirty piece of paper.

But perhaps no more accurately. I've seen Bunsen photometers in modern
physics labs, mounted on optical benches, and so on.


Problem with your Bunsen photometer, Nick, is that it only compares a very
narrow cone of light from each source. Needless to say, CF's come in all
shapes. The light emitted in one particular direction of one tube shape is
*not* the end all total story.

To make a better measurement, you would need to roll/pitch/yaw the test bulb
in all sorts of positions to measure the output in each direction. Or build
a test box with the interior surface lined with photometers.

Just comparing a typical incandescent (more or less globular) output with a
CF with a different shape is subject to these sorts of errors.

daestrom

On Sun, 16 Jul 2006 08:42:26 -0500, Bob Adkins
wrote:

On Sat, 15 Jul 2006 21:34:46 GMT, "C. Massey" wrote:


They why does my employer change out the fluorescent lighting about every 5
or 6 years even when they are all burning good? When they do, the rooms are
so much brighter. Makes a huge difference.

I'm betting the replacement was wasted. That's because the lamps were
changes individually as they failed. In other words, the average age of the
tubes they were changing out was far less than 5 years!

I have 14ea 48" tubes in my home, shop, and garage, and I'll bet the average
age is less than 2 years.


It is NOT out of the ordinary in commercial and institutional use, for
QUALITY tubes to last more than 3 years, and changing en mass before
failure is standard maintenance procedure. If maintenance needs to
change more than a few tubes before scheduled change-out, they either
modify the changeout schedule or find a new supplier!!!!!!!
5 years MIGHT be stretching it, but I know on office where in the last
5 years only 2 or 3 bulbs had been replaced (along with about 4
ballasts) before a mass relamping and reballasting took place.

--
Posted via a free Usenet account from http://www.teranews.com

On Sun, 16 Jul 2006 12:02:02 -0400, Neon John wrote:

On Sun, 16 Jul 2006 08:44:09 -0500, Bob Adkins
wrote:

Have you ever done a long term cost analysis on CF vs. incandescent? Does
the increased cost and short life of CF's negate the improved efficiency?

What short lives? I've been writing the install date on my CFs from
the beginning and have been keeping a log. Average life is about 4.5
years. The best one, a low wattage lamp in my bathroom that burns
24/7 is still going at 9+ years.

19 (if I counted right) 12W CFs here for over 7 years. One failure so
far at about 6 years.

When I can buy a pack of 5 from Sam's for $9, only a bit more than an
equivalent incandescent, the enconomics become a no-brainer.

Wayne

daestrom wrote:

Problem with your Bunsen photometer, Nick, is that it only compares a very
narrow cone of light from each source...

I suppose this problem diminishes with distance. A white paper reflector
behind each bulb might help.

Nick

Bob Adkins wrote:

I use Sylvania and GE, and sometimes they go out within a month. I do have 1
good CF that must be 7-8 years old, but most don't last a year.

Do you live in a rural area? Is it possible that your power has severe
fluctuations? Frequent lightning strikes? Unfortunately, rural power isn't as
clean as urban (as a crude generalization). That could contribute to your short
bulb life.

I use Phillips and 'Globe Energy Savers' (a brand in a big box hardware store)
and get years out of them. I'd say 4-5 years is typical for me and some last
longer.

Mike

C. Massey wrote:

They why does my employer change out the fluorescent lighting about every 5
or 6 years even when they are all burning good? When they do, the rooms are
so much brighter. Makes a huge difference.

The new fluorescent bulbs have a higher color temperature with more
blue light causing the perception of being much brighter.

--
Ron

In . com, Ron P. wrote:

C. Massey wrote:

They why does my employer change out the fluorescent lighting about every 5
or 6 years even when they are all burning good? When they do, the rooms are
so much brighter. Makes a huge difference.

The new fluorescent bulbs have a higher color temperature with more
blue light causing the perception of being much brighter.

I think more likely the phosphor degrades as the bulbs are used and the
replacement ones simply have full brightness.

There are many 4-foot fluorescent lamps now rated to last 20,000 or
24,000 hours, and that is with 3 operating hours per start. Expect a bit
more with one start per workday.

This means to me expect half to burn out in 5.5-6.5 years if used 10
hours a day 5 days a week and lasting no longer at 10 hours per start than
at 3 hours per start. Some installations will experience worse and some
will experience better.

Meanwhile, light output will decrease over the life of a fluorescent
lamp. It appears to me that a 32 watt T8 (1 inch diameter 4-footer) is
rated to be typically down about 5% in light output when 40% of the way
through its rated life, and I would expect about 10% down when getting
close to rated life. And it appears to me that typical phosphor
degradation is about double that for T12 (34 and 40 watt 1.5 inch
diameter) with older-tech phosphors.
I have known low-mercury ones to sometimes degrade faster due to the
mercury supply getting stuck in parts of the bulb from chemical reactions
and/or maybe mercury ions getting embedded into whatever, maybe in the
phosphor.

- Don Klipstein )

"Ron Peterson" wrote in message
ups.com...

C. Massey wrote:

They why does my employer change out the fluorescent lighting about every
5
or 6 years even when they are all burning good? When they do, the rooms
are
so much brighter. Makes a huge difference.

The new fluorescent bulbs have a higher color temperature with more
blue light causing the perception of being much brighter.



I don't care about "perception of being brighter", I just know that when
they do get changed out, you damn near have to wear sunglasses because it is
so bright.




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Ron Peterson wrote:
C. Massey wrote:


They why does my employer change out the fluorescent lighting about every 5
or 6 years even when they are all burning good? When they do, the rooms are
so much brighter. Makes a huge difference.


The new fluorescent bulbs have a higher color temperature with more
blue light causing the perception of being much brighter.


While this may be true in some cases, going from 2700K to 3100K to 3500K
or maybe even to 4100K can happen, but is unlikely.

They buy several cases of bulbs from the same supplier that they have
always dealt with, almost always buying the same bulb every time. The
bulbs do dim with age, and may be down to 50% of initial light output
just before failure. At 5-6 years of age on the lamps, on 12 or more
hours a day 5-7 days a week, light output may be down to 60-70% of
initial output.

So replacing Cool White lamps with new Cool White lamps WILL provide a
noticeable difference in overall lighting levels when a large area of
them that are 5-6 years old are replaced.

"Bob Adkins" wrote in message
...
On Sun, 16 Jul 2006 12:02:02 -0400, Neon John wrote:


When I can buy a pack of 5 from Sam's for $9, only a bit more than an
equivalent incandescent, the enconomics become a no-brainer.

I use Sylvania and GE, and sometimes they go out within a month. I do have
1
good CF that must be 7-8 years old, but most don't last a year.

What brands could you recommend that last longer than Sylvania and GE?
--
Bob

Any CFL brand that is Energy Star listed has to have lamp life tested and
the data supplied to Energy Star periodically to keep the listing. Energy
Star requires testing of other performance data too. See:
http://www.energystar.gov/ia/partner...s_prog_req.pdf

TKM

C. Massey wrote:
"Ron Peterson" wrote in message
ups.com...

The new fluorescent bulbs have a higher color temperature with more
blue light causing the perception of being much brighter.

I don't care about "perception of being brighter", I just know that when
they do get changed out, you damn near have to wear sunglasses because it is
so bright.

That's because the rods of the eye are more sensative to blue light and
the human eye has more rods than cones.

--
Ron

Don Klipstein wrote:
In . com, Ron P. wrote:

The new fluorescent bulbs have a higher color temperature with more
blue light causing the perception of being much brighter.

I think more likely the phosphor degrades as the bulbs are used and the
replacement ones simply have full brightness.

That also occurs. I am just repeating the recommendation of consultant
that was given to our building managers. The recommendation was to
increase the color temperature of the fluorescent lights.

There are many 4-foot fluorescent lamps now rated to last 20,000 or
24,000 hours, and that is with 3 operating hours per start. Expect a bit
more with one start per workday.

And that also depends on the type of ballast used.

--
Ron

In , TKM wrote:
(edited for space)
"Bob Adkins" wrote

I use Sylvania and GE, and sometimes they go out within a month. I do
have 1 good CF that must be 7-8 years old, but most don't last a year.

What brands could you recommend that last longer than Sylvania and GE?

Any CFL brand that is Energy Star listed has to have lamp life tested and
the data supplied to Energy Star periodically to keep the listing. Energy
Star requires testing of other performance data too. See:
http://www.energystar.gov/ia/partner...s_prog_req.pdf

I would like to add: Watch out for overheating CFs by putting them in
small enclosed fixtures and in downlights. Many CFs don't take this well,
and there is a general trend that this is worse with higher wattages.

Some actually rated to take the heat of recessed ceiling fixtures are
Philips SLS non-dimmables up to 23 watts.

I consider it notable that when I see recessed ceiling fixtures in
commercial buildings with CFs, the bulbs usually do not have built-in
ballasts and will not screw into "regular sockets". The ballast is
somewhere else in the fixture where it will not get as hot.

- Don Klipstein )