The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

On Jul 12, 12:57*pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

"alexander.keys1" wrote in message
...
On Jul 12, 12:57 pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for
incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating
and
therefore the rated wattage would be about the same regardless of the
type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

You have to be careful when you look at the ratings..

a long time ago the rating would be the maximum for a tungsten bulb and
would limit the temperature to a safe value for the *shade* (so it didn't
melt or burn) the lamp could run at near the melting point of the solder on
the base or higher if it were a capsule lamp with no base.

The same is true for a CFL, you could go to the same wattage and the *shade*
would be safe.

However CFLs will not run at the temperature that tungsten bulbs will and
can overheat in some shades even when they are well below the rating for the
shade. The same is true for LED bulbs even though they are only a few watts.

In general I avoid any shade that blocks ventilation, not doing so seriously
reduces the life of CFLs and LEDs.
It may be that argos are checking what is OK for CFL in each shade but I
doubt it.

dennis@home wrote:

snip


In general I avoid any shade that blocks ventilation, not doing so
seriously reduces the life of CFLs and LEDs.
It may be that argos are checking what is OK for CFL in each shade but
I doubt it.



From memory, all types and styles of shades (from paper globes with little
ventilation, to open fabric shades with unlimited ventilation) were marked
the same. None were given a rating 60W.

In article ,
"dennis@home" writes:


"alexander.keys1" wrote in message
...
On Jul 12, 12:57 pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for
incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating
and
therefore the rated wattage would be about the same regardless of the
type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

You have to be careful when you look at the ratings..

a long time ago the rating would be the maximum for a tungsten bulb and
would limit the temperature to a safe value for the *shade* (so it didn't
melt or burn) the lamp could run at near the melting point of the solder on
the base or higher if it were a capsule lamp with no base.

GLS (bog-standard filament lamps) are designed to run up to 200C.

The same is true for a CFL, you could go to the same wattage and the *shade*
would be safe.

However CFLs will not run at the temperature that tungsten bulbs will and
can overheat in some shades even when they are well below the rating for the

Retrofit CFL tubes are generally designed to run around 80-100C.
The electronics in the lamp base may be a little cooler, but since
they only have to last about 10,000 hours, the fact that they're
running near boiling point is just about viable. Each 10C temperature
rise generally halves the life of electronic circuits, so if you
operate it in a poorly ventilated fitting and it runs at 20C hotter
than it would in open air, the reduction to only 1/4 of the life
means that you'll probably start seeing some CFLs die due to ballast
failure before the tube wears out, and not realise the expected design
life across a reasonable sample size.

shade. The same is true for LED bulbs even though they are only a few watts.

LEDs have additional problems. They are destroyed at lower temperatures
than silicon semiconductors you'll find in a CFL ballast, so they have
to operate at lower temperatures. Secondly, they _are_ the source of heat
(whereas in a CFL, the tube is the source of heat and some separation
from the heat sensitive ballast can be achieved). Thirdly, the light
output (and efficiency) of most (if not all) LEDs drops dramatically
as they warm up, which makes being a source of heat a double whammy.
Turning a raw LED into a usable light requires significant thermal
design.

In general I avoid any shade that blocks ventilation, not doing so seriously
reduces the life of CFLs and LEDs.
It may be that argos are checking what is OK for CFL in each shade but I
doubt it.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:

In article ,
"dennis@home" writes:


"alexander.keys1" wrote in message
news:83ce919e-dd90-40bc-aeca-

...
On Jul 12, 12:57 pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for
incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent
overheating and
therefore the rated wattage would be about the same regardless of
the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue
compilers automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of
bulb.

You have to be careful when you look at the ratings..

a long time ago the rating would be the maximum for a tungsten bulb
and would limit the temperature to a safe value for the *shade* (so
it didn't melt or burn) the lamp could run at near the melting point
of the solder on the base or higher if it were a capsule lamp with no
base.

GLS (bog-standard filament lamps) are designed to run up to 200C.

The same is true for a CFL, you could go to the same wattage and the
*shade* would be safe.

However CFLs will not run at the temperature that tungsten bulbs will
and can overheat in some shades even when they are well below the
rating for the

Retrofit CFL tubes are generally designed to run around 80-100C.
The electronics in the lamp base may be a little cooler, but since
they only have to last about 10,000 hours, the fact that they're
running near boiling point is just about viable. Each 10C temperature
rise generally halves the life of electronic circuits, so if you
operate it in a poorly ventilated fitting and it runs at 20C hotter
than it would in open air, the reduction to only 1/4 of the life
means that you'll probably start seeing some CFLs die due to ballast
failure before the tube wears out, and not realise the expected design
life across a reasonable sample size.


So if a lampshade (or fitting or whatever) is rated for a 60W
incandescent lamp, what wattage CFL would you feel comfortable putting
in?

In article ,
Scion writes:
Andrew Gabriel wrote:

Retrofit CFL tubes are generally designed to run around 80-100C.
The electronics in the lamp base may be a little cooler, but since
they only have to last about 10,000 hours, the fact that they're
running near boiling point is just about viable. Each 10C temperature
rise generally halves the life of electronic circuits, so if you
operate it in a poorly ventilated fitting and it runs at 20C hotter
than it would in open air, the reduction to only 1/4 of the life
means that you'll probably start seeing some CFLs die due to ballast
failure before the tube wears out, and not realise the expected design
life across a reasonable sample size.


So if a lampshade (or fitting or whatever) is rated for a 60W
incandescent lamp, what wattage CFL would you feel comfortable putting
in?

Difficult to come up with a hard and fast rule.
Off the top of my head, I would suggest...

If the fitting is flammable (e.g. a paper lantern), stick with
no more than 1/4 of the max incandescent wattage.

If the fitting is enclosed (no convective airflow), probably stick
to no more than 1/4 of the max incandescent lamp. If it's all
fireproof materials, you could go higher if you don't mind reduced
lamp life.

If the fitting is well ventilated with convective airflow, can
probably go up to 1/2 the max incandescent wattage.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In message
,
alexander.keys1 writes
On Jul 12, 12:57*pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

Yebbut.........
While the light output may be the same, isn't a 60W incandescent a lot
hotter than a 12W CFL?
--
Ian

On 12/07/2011 13:46, Ian Jackson wrote:
In message
,
alexander.keys1 writes
On Jul 12, 12:57 pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for
incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent
overheating and
therefore the rated wattage would be about the same regardless of the
type
of lamp.

Is it me missing something obvious or is it the Argos catalogue
compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

Yebbut.........
While the light output may be the same, isn't a 60W incandescent a lot
hotter than a 12W CFL?

Absolutely!
I make stained-glass lamps that use CFL lamps. An equivalent wattage
incandescent gets far hotter then the CFL...

Adrian

In message , Ian Jackson
writes
In message
,
alexander.keys1 writes
On Jul 12, 12:57*pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

Yebbut.........
While the light output may be the same, isn't a 60W incandescent a lot
hotter than a 12W CFL?

I have no idea what I'm talking about, but maybe type of heat and source
of heat might make a difference. Are incandescents not producing more
radiant heat and also heating up a relatively large area - the glass?

Do CFL's not produce heat in the base and so maybe have less watts, but
in a more restricted area?
--
Bill

On Jul 12, 1:27*pm, "alexander.keys1"
wrote:
On Jul 12, 12:57*pm, Scion wrote:

The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

If that were the case you could fit a much larger CFLthan tungsten.
The reason is that a tungsten lamp can run in a much hotter
environment than a CFL.

Tim Streater wrote:
In article
,
"alexander.keys1" wrote:

On Jul 12, 12:57Â*pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

It's because of the heat emitted by the bulb, not the current drawn,
the heat production is equal to the wattage for whatever type of bulb.

I think the Argos people don't have a clue simply enough. A 12W CFL will
be a damn sight cooler than a 60W tungsten.

Further, 5 of them, drawing 60W in total, will also I assert emit less
heat than a single tungsten, because more of the energy supplied goes
into producing light, and less goes into producing heat.

Except that all of the light will end up as heat anyway, where else do
you think the energy goes? However I suppose there will be slightly
less heat in the lampshade.

--
Chris Green

On 12 July, 18:45, wrote:
Tim Streater wrote:

Further, 5 of them, drawing 60W in total, will also I assert emit less
heat than a single tungsten, because more of the energy supplied goes
into producing light, and less goes into producing heat.

Less, but not much less. One lumen is 1/683 W. According to
http://www.mge.com/home/appliances/l...comparison.htm, a good
incandescent bulb can generate ~20 lumens / W, so to a first
approximation *zero* electricity is turned into light.

A good CFL can generate 68 lumens/W - but that still means that 90% of
the electricity is turned into heat.

Except that all of the light will end up as heat anyway, where else do
you think the energy goes? *However I suppose there will be slightly
less heat in the lampshade.

The light will end up as heat - but as heat in the walls, furnishings,
and other absorbent surfaces around the room. However, as noted
above, even with a really good CFL (or even a high pressure sodium
street light), nearly all the electricity turns straight into heat.

In article ,
Martin Bonner writes:
On 12 July, 18:45, wrote:
Tim Streater wrote:

Further, 5 of them, drawing 60W in total, will also I assert emit less
heat than a single tungsten, because more of the energy supplied goes
into producing light, and less goes into producing heat.
Less, but not much less. One lumen is 1/683 W. According to
http://www.mge.com/home/appliances/l...comparison.htm, a good

That's a good chart, although I can't see why it's done as flash.

A couple of points - LED lights that achieve even 50 l/W are
currently prohibitively expensive, never mind the 60 figure it
suggests. Most of the cheap consumer LED lamps are same effiency
as halogens.

A shame it's missing low pressure sodium - the higher power ones
are around 220 l/W, and are the most efficent mass produced light
source available.

An interesting problem is that they are too efficient to heat
the sodium enough. If you run one in an oven, they reach
300 l/W, but take it out of the oven, and at 300 l/W there's not
enough heat being generated to keep enough sodium vaporised so it
will dim back down until its efficiency is reduced to the point
where it generates enough heat, and settles at about 220 l/W.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:

Martin Bonner writes:

http://www.mge.com/home/appliances/l...comparison.htm

That's a good chart, although I can't see why it's done as flash.

Especially since that means the images below it don't align with the bars.

On Jul 12, 12:57*pm, Scion wrote:
The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

On the occasions that I've looked at the Argos purchaser guides, I've
never yet seen one that has a clue what its talking about.


NT

"Scion" wrote in message
.. .
The Argos catalogue has lampshades with different ratings for incandescent
and CFL lamps. e.g. Rated for 60W incandescent or 12W CFL.

What's that all about - I thought the rating was to prevent overheating
and
therefore the rated wattage would be about the same regardless of the type
of lamp.

Is it me missing something obvious or is it the Argos catalogue compilers
automatically converting one to the other?

Yes. Just a bit more nonsense that this crap technology has thrown up to
confuse the general public. As an aside, I believe that there was a heated
debate in the US senate about CFLs last week ...

Arfa