Once again the hot weather has reminded me of just how much I dislike it!
Last night I noticed the amount of heat given of by my ordinary bedside
lamp - IIRC something like 80% of the energy in light bulbs is heat not
light. It made me wonder whether different bulbs would produce less heat?

Argos do a pack of 3 15 Watt BC Energy Saving Fluorescent Bulbs for £6.99

http://www.argos.co.uk/webapp/wcs/st...y?storeId=1000
1&langId=-1&catalogId=2501&productId=104088

These seem to have an ordinary 'bayonet' type fixing. Would these emit less
heat as well as being more efficient?

Can anyone shed some light on the subject?

Richard Blackwood wrote:

Once again the hot weather has reminded me of just how much I dislike it!
Last night I noticed the amount of heat given of by my ordinary bedside
lamp - IIRC something like 80% of the energy in light bulbs is heat not
light. It made me wonder whether different bulbs would produce less heat?


A lot more than 80% - more like 95%.


Argos do a pack of 3 15 Watt BC Energy Saving Fluorescent Bulbs for £6.99
These seem to have an ordinary 'bayonet' type fixing. Would these emit less
heat as well as being more efficient?

Yes, they will give out a lot less heat. The only problem with CFs
(compact fluorescents; what these are) is the colour temperature. Many
(most?) of the cheaper ones have a truly horrible spectrum, and
everything end up looking yellow. You need to find some that you are
happy with. Personally I like Phillips ones, and have used them a lot.


--
Grunff

Yes, they will give out a lot less heat. The only problem with CFs
(compact fluorescents; what these are) is the colour temperature.

Not only that, some can take a while before they start to emit their
stated "equivalent" output...

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"Colin Wilson" wrote in message
t...
Yes, they will give out a lot less heat. The only problem with CFs
(compact fluorescents; what these are) is the colour temperature.

Not only that, some can take a while before they start to emit their
stated "equivalent" output...

Sometimes; you have to switch ON a CF 'bulb' in the morning if
you want to read by it in the evening! OK! That's a slight hyperbole;
but they are slow to come to full brilliance. They are fine for
lamps which will be ON for hours ... but not for places where
the lights will be switched ON for short periods (toilets, bathrooms,
bedside lamps, for instance)

--

Brian

Brian Sharrock wrote:

Sometimes; you have to switch ON a CF 'bulb' in the morning if
you want to read by it in the evening! OK! That's a slight hyperbole;
but they are slow to come to full brilliance. They are fine for
lamps which will be ON for hours ... but not for places where
the lights will be switched ON for short periods (toilets, bathrooms,
bedside lamps, for instance)


Again, I've found this to vary greatly between makes. Some are very
poor, taking 10mins or more to reach max output, while others do so in a
few seconds.

--
Grunff

"Grunff" wrote in message
...
Brian Sharrock wrote:

Sometimes; you have to switch ON a CF 'bulb' in the morning if
you want to read by it in the evening! OK! That's a slight hyperbole;
but they are slow to come to full brilliance. They are fine for
lamps which will be ON for hours ... but not for places where
the lights will be switched ON for short periods (toilets, bathrooms,
bedside lamps, for instance)


Again, I've found this to vary greatly between makes. Some are very
poor, taking 10mins or more to reach max output, while others do so in a
few seconds.


The time is actually programmed in by the manufacturer. Most now use the
STMicroelectronics chip and it is easy to set this from 1 second to days.
The slower it turns on the longer the tube will last.

"Brian Sharrock" wrote in message
...

"Colin Wilson" wrote in message
t...
Yes, they will give out a lot less heat. The only problem with CFs
(compact fluorescents; what these are) is the colour temperature.

Not only that, some can take a while before they start to emit their
stated "equivalent" output...

Sometimes; you have to switch ON a CF 'bulb' in the morning if
you want to read by it in the evening! OK! That's a slight hyperbole;
but they are slow to come to full brilliance. They are fine for
lamps which will be ON for hours ... but not for places where
the lights will be switched ON for short periods (toilets, bathrooms,
bedside lamps, for instance)

--

Brian



I have them in our bed side lamps and they are much better than standard
lamps.

Steve Dawson

"Stephen Dawson" wrote in message
...

"Brian Sharrock" wrote in message
...

"Colin Wilson" wrote in message
t...
Yes, they will give out a lot less heat. The only problem with CFs
(compact fluorescents; what these are) is the colour temperature.

Not only that, some can take a while before they start to emit their
stated "equivalent" output...

Sometimes; you have to switch ON a CF 'bulb' in the morning if
you want to read by it in the evening! OK! That's a slight hyperbole;
but they are slow to come to full brilliance. They are fine for
lamps which will be ON for hours ... but not for places where
the lights will be switched ON for short periods (toilets, bathrooms,
bedside lamps, for instance)

--

Brian



I have them in our bed side lamps and they are much better than standard
lamps.


OK; Steve: lets parse your sentence: -
I said they (CF lamps) are fine for situations were the lamp
will be ON for 'ages' - you said that you use them at your bedside -
implication: I only switch on the bedside lamps for short periods
while you keep yours ON for longish periods.
As the sayiing goes YMMV!

I've not heard of anyone using standard lamps by the bed sides.
I agree with you that, for this purpose, bed-side lamps (either
table-supported or wall-hung) are better than standard lamps.

--

Brian

In article ,
Colin Wilson writes:
Yes, they will give out a lot less heat. The only problem with CFs
(compact fluorescents; what these are) is the colour temperature.

The colour temperature of pretty well all those you can buy is 2700K,
same as a filament lamp (and intentionally so).

Not only that, some can take a while before they start to emit their
stated "equivalent" output...

Which can be really handy in a bedside light.

--
Andrew Gabriel

Not only that, some can take a while before they start to emit their
stated "equivalent" output...

Which is absolutely brilliant for a bedside light. I would NEVER fit an
incandescent light for this, for several reasons.

1. Energy efficiency (obviously)
2. Safety. (bulb temperature when half asleep)
3. Eye comfort when turning on at night.

I'm having to get up several times a night to change nappies etc. at the
moment. The fact that you don't have a tear inducing, retina rupturing 100W
of light down your eyeball as soon as you turn on the light is excellent. My
bulbs have exactly the right warm up time to get your eyes going in a gentle
fashion.

I have burnt myself several times on incandescent bulbs before low wattage
ones became available. I suffer from sleep walking.

Christian.

In article ,
Christian McArdle wrote:
I'm having to get up several times a night to change nappies etc. at the
moment. The fact that you don't have a tear inducing, retina rupturing
100W of light down your eyeball as soon as you turn on the light is
excellent.

Heh heh. Think the first room I equipped with a dimmer was a bedroom.

In my bedroom, they're all accessible from the bed - including reading
lamp ones either side - with an overall master two way switched from the
bed and door.

--
*When cheese gets its picture taken, what does it say? *

Dave Plowman London SW
To e-mail, change noise into sound.

Christian McArdle wrote:

I'm having to get up several times a night to change nappies etc. at the
moment. The fact that you don't have a tear inducing, retina rupturing 100W
of light down your eyeball as soon as you turn on the light is excellent. My

I think it took about three days after getting our first sprog home
before deveoping a deep afection for dimmer switches; which got fitted
all over the place ;-)



--
Cheers,

John.

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Richard Blackwood wrote:
Once again the hot weather has reminded me of just how much I dislike it!
Last night I noticed the amount of heat given of by my ordinary bedside
lamp - IIRC something like 80% of the energy in light bulbs is heat not
light. It made me wonder whether different bulbs would produce less heat?

Ulitmately it's *all* heat, it's just that the light gets turned into
heat further from the lamp. The only energy you lose is the amount
that goes out of the window as light - not much.

--
Chris Green

"Richard Blackwood" wrote in message
...
Once again the hot weather has reminded me of just how much I dislike it!
Last night I noticed the amount of heat given of by my ordinary bedside
lamp - IIRC something like 80% of the energy in light bulbs is heat not
light. It made me wonder whether different bulbs would produce less heat?

Argos do a pack of 3 15 Watt BC Energy Saving Fluorescent Bulbs for £6.99

http://www.argos.co.uk/webapp/wcs/st...y?storeId=1000
1&langId=-1&catalogId=2501&productId=104088

These seem to have an ordinary 'bayonet' type fixing. Would these emit
less
heat as well as being more efficient?

Being "more efficient" and "emitting less heat" are two sides of the same
coin. It is precisely because incandescent bulbs convert so much of the
electrical energy into heat, that they are inefficient as light sources. So,
the answer to that last question is most definitely "yes".

Older types of energy saving bulb had rather primitive ballasts in the base,
so used to get quite warm themselves and weren't as efficient as the makers
would have you believe, but the newer ones with electronic ballasts run much
cooler.

Rick

but the newer ones with electronic ballasts run much cooler.

I should mention that it is quite possible to touch many types of low energy
lamp whilst still on. They are usually quite hot, but within the tolerance
of most people.

Christian.

Christian McArdle wrote:

but the newer ones with electronic ballasts run much cooler.


I should mention that it is quite possible to touch many types of low energy
lamp whilst still on. They are usually quite hot, but within the tolerance
of most people.

same is true for a 40w incandescent I find...

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

same is true for a 40w incandescent I find...

You have a higher tolerance than me! 20W is about my limit...

Christian.

"John Rumm" wrote in message
...
Christian McArdle wrote:

but the newer ones with electronic ballasts run much cooler.


I should mention that it is quite possible to touch many types of low
energy
lamp whilst still on. They are usually quite hot, but within the
tolerance
of most people.

same is true for a 40w incandescent I find...

You're a chef ? Or an exhaust mechanic ? Or ... ?

"Richard Blackwood" wrote in message ...
Once again the hot weather has reminded me of just how much I dislike it!
Last night I noticed the amount of heat given of by my ordinary bedside
lamp - IIRC something like 80% of the energy in light bulbs is heat not
light. It made me wonder whether different bulbs would produce less heat?

Argos do a pack of 3 15 Watt BC Energy Saving Fluorescent Bulbs for £6.99

http://www.argos.co.uk/webapp/wcs/st...y?storeId=1000
1&langId=-1&catalogId=2501&productId=104088

These seem to have an ordinary 'bayonet' type fixing. Would these emit less
heat as well as being more efficient?

Can anyone shed some light on the subject?


All a bulbs power input becomes heat: about 98% of it becomes heat
directly, the rest becomes light, which turns to heat less than a
microsecond later as its absorbed. The power input always equals the
heat output.

CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects. The real efficiency
improvement is about 3.5x - 4x, so to replace a 60w bulb you need a
15-17 watts.

If you trust the box's equivalency claims, its dimmer and doesnt look
right.


NT

CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects.

I'm not sure I quite buy that. I think the equivalency is about right, but
you must run the bulb for five minutes before you make the comparison.

Christian.

"Christian McArdle" wrote in message .net...
CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects.

I'm not sure I quite buy that. I think the equivalency is about right, but
you must run the bulb for five minutes before you make the comparison.

Christian.


theyre compared to soft light bulbs, which have lower light output
than standard GLS ones.

Unfortunately this dim practice is their downfall, as it has led to
the popular perception that their light is inferior.


Regards, NT

"N. Thornton" wrote in message
om...
"Richard Blackwood" wrote in message
...

All a bulbs power input becomes heat: about 98% of it becomes heat
directly, the rest becomes light, which turns to heat less than a
microsecond later as its absorbed. The power input always equals the
heat output.

CFLs are the solution, but dont be caught out by the one issue: the
stated equivalent powers are unrealistic, as they are comparisons with
a different type of bulb than everyone expects. The real efficiency
improvement is about 3.5x - 4x, so to replace a 60w bulb you need a
15-17 watts.

If you trust the box's equivalency claims, its dimmer and doesnt look
right.


I must agree that the equivalencies do seem rather on the optimistic side,
to put it kindly.

Rick

On 8 Sep 2004 07:44:22 -0700, N. Thornton wrote:

If you trust the box's equivalency claims, its dimmer and doesnt
look right.

Yep, been caught like that. I now look for the little box that gives
the techy information, like (but not always) voltage, fitting code,
life, lumens, colour temperature.

For example a 60W incandescant has "240V 700 Lumen 1000h" on the
bottom of the box. Morrisons (=A32.99 for 2) 11W CFLs have "711 Lumen 11=

Watt 12000h". I have yet to try these cheapies and I'm fully expecting
the colour to be crap...

You can get decent colour temperature CFLs now though, just replaced
6x40W E14 candles with GE Tech Extra Mini 9W CFLs, there is actually
more light in the room now. Not cheap, =A36.98 each springs to mind from=

B&Q, but as these lights are on for 18hrs a day the reduction in the
power bill will have paid for them in about 9 months...

--
Cheers
Dave. pam is missing e-mail