Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Season misconceptions in newspaper



"I don't think there is an efficiency rating
standard for light bulbs yet, the way there is such a standard for air
conditioners."


Not yet in California, however, the state govt. either itself or by
"leaning" on PG&E has subsidized compact fluorescents to the extent that
the one's at Costco are less expensive than incandescents at retailers!

The claim is ~ 3X efficiency (lumens / Watt) It's quite easy to
check using a Watmeter (NOT Volt-Ameter) and ones camera light meter;
use far field distance for same reading. Big assumption: meter
imitates eye's response.

John Clement wrote:

I do not know where the tag is at this time, so I will have to tell you
what I recall. It was a very simple tag and anyone with half a brain
could see that they were implying that the 60W halogen bulb would save
money because it was more efficient than a regular 60W light bulb. I
made an overhead slide of it and students could readily see the fallacy
in the statement It didn't save money in electricity whether or not it
was more efficient. If more efficient they should have compared it with
a standard higher wattage bulb with identical light output. The tag
said nothing about bulb life.

Essentially it was a case of an advertising copywriter making a stupid
statement. Of course this is exactly the sort of thing that creeps into
committee written texts. Unfortunately most consumers would just look
at the claim and not the extra information. It is a good example of why
science teaching is badly in need of reform. If consumers used their
brains more, such copy would be so laughable that writers would cease to
produce it.

I have also seen efficiency claims being made for other halogen bulbs
which have similar light output compared to standard bulbs of the same
wattage. You probably can go to any large hardware store and see this
sort of advertising copy. I haven't looked lately, but I suspect these
claims are still there. I don't think there is an efficiency rating
standard for light bulbs yet, the way there is such a standard for air
conditioners.

And yes, fluorescents are the way to go, but only if they have been well
made. One popular brand has a short lifetime and as a result is not a
bargain according to Consumer Reports.

John M. Clement
Houston, TX




What units did the tags use?

Are you certain it was lamp cost saving and not electricity?

there are two competing factors in incandescent lamps, life and


luminous


efficiency. Halogen cycle lamps may be operated at the temperature of
std. gas filled lamps, and, thereby, have a considerably longer life.
From an old table (< '68 ca.) two comparable lamps:

Both std. and Iodine cycle (quartzline) 500 W operated at a color


Temp.


of 3200. They both emit ~ 10K Lumens; the iodine has a life of 2,000
hr.., the std (CZX projection) only 25 hr..

more info. including a reflection coating that much increases the
efficiency:

http://www.lampcenter.com/halog_2en.htm

bc whose home is almost completely fluorescently lighted




John Clement wrote:



That may be true, but the tag actually implied you were saving
electricity. It did not have any information about lifetime or bulb
cost. It looked so impressive until you read the actual information.

What surprised me is that 60W halogen bulbs have comparable rated


light


output to 60W regular bulbs the last time I looked at them in the


store.


They usually have some claims about being "more efficient". Perhaps
they put out more light in the more visible portion of the spectrum


to


validate the claim of higher efficiency?

Things have not changed since they sold in radio ads genuine 14 carat
simulated gold rings.

John M. Clement
Houston, TX





-----Original Message-----
From: Forum for Physics Educators [mailto:PHYS-L@lists.nau.edu] On




Behalf




Of Tim Folkerts
Sent: Saturday, June 21, 2003 3:32 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Season misconceptions in newspaper





I have an interesting tag that I stole from a lamp in a store. It
claims that an expensive lamp which uses a 60 W halogen bulb is


more


efficient and saves money over a conventional 60 W bulb. I


compared




the




rated lumens and wattage with a conventional light bulb and found




they




were comparable. Hmmm I have asked students whether the claim was
true.




Of course, if the halogen bulb costs 3x as much, but lasts 10x


longer,


then
it DOES save money!


Timothy Folkerts


"The only thing necessary for the triumph of evil is for good men to




do




nothing." - Edmund Burke