I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

Peter Scott

I know that with tungsten filament it saved very little as the light was
a tiny part of the output.

How do you know it only saves very little? Are you saying that when dimming
a tunsten filament lamp only the light energy component is reduced and not
the heat?


mark

In article , mark
writes


I know that with tungsten filament it saved very little as the light was
a tiny part of the output.

Are you saying that when dimming
a tunsten filament lamp only the light energy component is reduced and not
the heat?

It is true that light output falls off far more rapidly than heat when
dimming incandescent lamps, expect (roughly): 50% dimmed, 75% power use,
75% dimmed, 50% power use.

For the o/p, my belief is that the dimming process will be far more
efficient than for incandescents but I have no cite for this, it should
certainly be the case for purpose built dimming electronic ballasts but
I'm uncertain how effective the use of a conventional dimmer on an
incandescent replacement low energy lamp would be.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

mark wrote:
I know that with tungsten filament it saved very little as the light was
a tiny part of the output.

How do you know it only saves very little? Are you saying that when dimming
a tunsten filament lamp only the light energy component is reduced and not
the heat?


mark


Previous threads in this ng have cited figures showing a disappointing
energy reduction. I used dimmers a lot assuming that it was saving
energy. Unfortunately hooking up an energy meter to read the data from a
wall-mounted dimmer would be a non-trivial task. But if no-one has any
data perhaps I'll use an ammeter and voltmeter and take some measurements.

Peter Scott

On Mon, 16 Feb 2009 10:16:16 +0000 someone who may be Peter Scott
wrote this:-

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light.

I wait with interest to see whether the usual suspects come along
and make loud and long complaints about this assertion.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Feb 16, 11:58*am, Peter Scott wrote:
mark wrote:
I know that with tungsten *filament it saved very little as the light was
a tiny part of the output.

How do you know it only saves very little? Are you saying that when dimming
a tunsten filament lamp only the light energy component is reduced and not
the heat?

mark

Previous threads in this ng have cited figures showing a disappointing
energy reduction. I used dimmers a lot assuming that it was saving
energy. Unfortunately hooking up an energy meter to read the data from a
wall-mounted dimmer would be a non-trivial task. But if no-one has any
data perhaps I'll use an ammeter and voltmeter and take some measurements..

I fear you'll need a power meter - the current and voltage may be
significantly out of phase with all the electronics + non-symmetrical
wave-forms.

In article ,
Peter Scott wrote:
I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

Can you tell me what sort of low-energy lamps these are that work with
conventional dimmers please? (and where to get them)

I've a couple of chandalier type things with 200W worth of incandescants
in which I'd really like to replace with CFLs, but they'd need to be
dimmable..

Gordon

In article ,
Gordon Henderson wrote:
In article ,
Peter Scott wrote:
I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

Can you tell me what sort of low-energy lamps these are that work with
conventional dimmers please? (and where to get them)

I've a couple of chandalier type things with 200W worth of incandescants
in which I'd really like to replace with CFLs, but they'd need to be
dimmable..

Actually, scratch that, I've just seen this:

http://www.tlc-direct.co.uk/Products/MGGU11D.html

and others in the same range..

Gordon

In article ,
Peter Scott writes:
I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

I would expect energy consumption will match light output
for any fluorescent, at least to a first order. When dimmed
below about 50%, it's necessary to provide power to heat
the electrodes, and that might be significant in short
compact fluorescents. Some dimming control gear does this
all the time in any case.

I haven't actually measured the load, although I could do so
when I get a spare moment.

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

David Hansen wrote:

On Mon, 16 Feb 2009 10:16:16 +0000 someone who may be Peter Scott
wrote this:-

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light.

I wait with interest to see whether the usual suspects come along
and make loud and long complaints about this assertion.

Why?

The OP said he was "very happy". I'm certainly not going to argue that
he's actually putting a brave face on hiding his unhappiness.

Sid

In article ,
David Hansen wrote:
I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light.

I wait with interest to see whether the usual suspects come along
and make loud and long complaints about this assertion.

Why? It's a perfectly reasonable point in the context of the subject.

--
*Hard work has a future payoff. Laziness pays off NOW.

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

Peter Scott wrote:

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

Peter Scott

CFLs, like any fluorescent tube, dissipate power in 2 places
1. the ends of the tube
2. the long discharge path

Most of the energy used goes in the latter, and this is wha produces
light. So for small amounts of dimming your energy use is pretty much
proportional to light output. As you dim heavily, you still get a lot
of power reduction, but not quite as much as proportional to light
output.

There is another effect, that phosphor efficiency varies a little
depending on light output, but not hugely.

In short these perform way better than tungsten filaments, in this
respect, with energy the saving being almost as much as the light
reduction you see.


NT

wrote:

David Hansen wrote:

On Mon, 16 Feb 2009 10:16:16 +0000 someone who may be Peter Scott
wrote this:-

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light.
I wait with interest to see whether the usual suspects come along
and make loud and long complaints about this assertion.

Why?

The OP said he was "very happy". I'm certainly not going to argue that
he's actually putting a brave face on hiding his unhappiness.

Sid

Could be both at once like a cubist painting!!!!

Gordon Henderson wrote:
In article ,
Gordon Henderson wrote:
In article ,
Peter Scott wrote:
I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.
Can you tell me what sort of low-energy lamps these are that work with
conventional dimmers please? (and where to get them)

I've a couple of chandalier type things with 200W worth of incandescants
in which I'd really like to replace with CFLs, but they'd need to be
dimmable..

Actually, scratch that, I've just seen this:

http://www.tlc-direct.co.uk/Products/MGGU11D.html

and others in the same range..

Gordon

Make sure you check the size. The bases are a bit bigger than usual
perhaps. I got mine from CPC at just under a tenner.

Peter Scott

wrote:
Peter Scott wrote:

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

Peter Scott

CFLs, like any fluorescent tube, dissipate power in 2 places
1. the ends of the tube
2. the long discharge path

Most of the energy used goes in the latter, and this is wha produces
light. So for small amounts of dimming your energy use is pretty much
proportional to light output. As you dim heavily, you still get a lot
of power reduction, but not quite as much as proportional to light
output.

There is another effect, that phosphor efficiency varies a little
depending on light output, but not hugely.

In short these perform way better than tungsten filaments, in this
respect, with energy the saving being almost as much as the light
reduction you see.


NT

Thanks. That was the comment I hoped to hear. Taking note of the earlier
thread about phase difference, I'll drag out my second meter (wherever
it is) and try to get a reading. Your comments sound most encouraging. I
think, once dimmed, the colour temperature of 'warm' 2700K lamps is fine
for me. But each to his own.

Peter Scott

In article ,
Peter Scott writes:

Thanks. That was the comment I hoped to hear. Taking note of the earlier
thread about phase difference, I'll drag out my second meter (wherever
it is) and try to get a reading. Your comments sound most encouraging. I
think, once dimmed, the colour temperature of 'warm' 2700K lamps is fine
for me. But each to his own.

Colour of fluorescents change as you dim them because
the relative intensities of the spectral lines change.
Different brands and types may well change differently.

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

On Mon, 16 Feb 2009 12:38:16 +0000, David Hansen
wrote:

I wait with interest to see whether the usual suspects come along
and make loud and long complaints about this assertion.

They would but they all got stuck in a snowdrifts while going for
plumbing spares to fix the frozen pipes caused by the global warming.

In article ,
Andrew Gabriel wrote:
Colour of fluorescents change as you dim them because
the relative intensities of the spectral lines change.
Different brands and types may well change differently.

Nothing like as big a change as tungsten, though. To the point where I'm
not really aware of it here.

--
*I speak fluent patriarchy but it's not my mother tongue

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

conventional dimmers please? (and where to get them)

I've a couple of chandalier type things with 200W worth of incandescants
in which I'd really like to replace with CFLs, but they'd need to be
dimmable..

Gordon

Just open the window and let a bit of cold air into the room. That'll dim
any type of CFL pretty successfully ... d;~}

Arfa

"Peter Scott" wrote in message
news
wrote:
Peter Scott wrote:

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

Peter Scott

CFLs, like any fluorescent tube, dissipate power in 2 places
1. the ends of the tube
2. the long discharge path

Most of the energy used goes in the latter, and this is wha produces
light. So for small amounts of dimming your energy use is pretty much
proportional to light output. As you dim heavily, you still get a lot
of power reduction, but not quite as much as proportional to light
output.

There is another effect, that phosphor efficiency varies a little
depending on light output, but not hugely.

In short these perform way better than tungsten filaments, in this
respect, with energy the saving being almost as much as the light
reduction you see.


NT

Thanks. That was the comment I hoped to hear. Taking note of the earlier
thread about phase difference, I'll drag out my second meter (wherever it
is) and try to get a reading. Your comments sound most encouraging. I
think, once dimmed, the colour temperature of 'warm' 2700K lamps is fine
for me. But each to his own.

Peter Scott

Any readings that you get *may* be pretty meaningless, as the electronic
ballast in CFLs is a crude switch mode power supply which has a 'pulsy' and
very likely asymmetric draw from the mains in the first place, and then to
make things worse, you are hitting it with partial cycles from the circuitry
in the dimmer. All of this may combine to produce a power draw which is of
such an odd shape that the power meter is not able to make true sense of it
to the point where it produces a meaningful reading.

Arfa

Arfa Daily wrote:
"Peter Scott" wrote in message
news
wrote:
Peter Scott wrote:

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light. My first experiment with one lamp was a failure. It didn't load
the dimmer enough. Most seem to need a minimum of 40W.

Question is does dimming save much energy? I know that with tungsten
filament it saved very little as the light was a tiny part of the
output. Has anyone measured, or seen figures for, the energy saving for
CFLs? My searches have revealed nothing.

Peter Scott
CFLs, like any fluorescent tube, dissipate power in 2 places
1. the ends of the tube
2. the long discharge path

Most of the energy used goes in the latter, and this is wha produces
light. So for small amounts of dimming your energy use is pretty much
proportional to light output. As you dim heavily, you still get a lot
of power reduction, but not quite as much as proportional to light
output.

There is another effect, that phosphor efficiency varies a little
depending on light output, but not hugely.

In short these perform way better than tungsten filaments, in this
respect, with energy the saving being almost as much as the light
reduction you see.


NT
Thanks. That was the comment I hoped to hear. Taking note of the earlier
thread about phase difference, I'll drag out my second meter (wherever it
is) and try to get a reading. Your comments sound most encouraging. I
think, once dimmed, the colour temperature of 'warm' 2700K lamps is fine
for me. But each to his own.

Peter Scott

Any readings that you get *may* be pretty meaningless, as the electronic
ballast in CFLs is a crude switch mode power supply which has a 'pulsy' and
very likely asymmetric draw from the mains in the first place, and then to
make things worse, you are hitting it with partial cycles from the circuitry
in the dimmer. All of this may combine to produce a power draw which is of
such an odd shape that the power meter is not able to make true sense of it
to the point where it produces a meaningful reading.

Arfa


That makes sense Arfa. I guess you just saved me trying to find my croc
clip probes or risking blue lights!

In summary then, CFLs almost certainly save more energy than tungsten
lamps when dimmed. It's best to buy all lamps from the same batch when
dimming more than one to ensure they glow the same. Until they devise
low power dimmers you must have more than one lamp or you won't load a
dimmer properly.

Thanks to all for comments.

Peter Scott

In article ,
"Dave Plowman (News)" writes:
In article ,
Andrew Gabriel wrote:
Colour of fluorescents change as you dim them because
the relative intensities of the spectral lines change.
Different brands and types may well change differently.

Nothing like as big a change as tungsten, though. To the point where I'm
not really aware of it here.

The colour shift as something cools and dims seems to be programmed
into our brains as expected behaviour. (That effect has a name which
I can't remember, i.e. the way you expect higher lighting levels to
have higher colour temperature).

With fluorescent tubes, the colour changes in less predictable ways.
With some I have, they tend to go purple (probably a loss of green
components), and I strongly suspect the CRI drops considerably,
although I have no way to measure that. The drop in CRI and change
of colour probably make any change in colour temperature meaningless,
although very likely.

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

In article ,
Andrew Gabriel wrote:
Nothing like as big a change as tungsten, though. To the point where I'm
not really aware of it here.

The colour shift as something cools and dims seems to be programmed
into our brains as expected behaviour. (That effect has a name which
I can't remember, i.e. the way you expect higher lighting levels to
have higher colour temperature).

With fluorescent tubes, the colour changes in less predictable ways.
With some I have, they tend to go purple (probably a loss of green
components), and I strongly suspect the CRI drops considerably,
although I have no way to measure that. The drop in CRI and change
of colour probably make any change in colour temperature meaningless,
although very likely.

We use dimmable fluorescents for TV lighting - and I've not noticed the LD
having to compensate noticeably when dimming them. As he certainly would
have to do with tungsten. To the point where they wouldn't normally dim
tungsten but use ND filters.

--
*There are two kinds of pedestrians... the quick and the dead.

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

In article ,
"Dave Plowman (News)" writes:
In article ,
Andrew Gabriel wrote:
Nothing like as big a change as tungsten, though. To the point where I'm
not really aware of it here.

The colour shift as something cools and dims seems to be programmed
into our brains as expected behaviour. (That effect has a name which
I can't remember, i.e. the way you expect higher lighting levels to
have higher colour temperature).

With fluorescent tubes, the colour changes in less predictable ways.
With some I have, they tend to go purple (probably a loss of green
components), and I strongly suspect the CRI drops considerably,
although I have no way to measure that. The drop in CRI and change
of colour probably make any change in colour temperature meaningless,
although very likely.

We use dimmable fluorescents for TV lighting - and I've not noticed the LD
having to compensate noticeably when dimming them. As he certainly would
have to do with tungsten. To the point where they wouldn't normally dim
tungsten but use ND filters.

My guess is you are using something special and expensive, possibly
even something specially designed for dimming, and not bog standard
colour 830 or similar. There are fluorescent lamp controllers which
drive multiple tubes of different colour [temperatures] to create
variable colour temperature output.

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

In article ,
Andrew Gabriel wrote:
We use dimmable fluorescents for TV lighting - and I've not noticed
the LD having to compensate noticeably when dimming them. As he
certainly would have to do with tungsten. To the point where they
wouldn't normally dim tungsten but use ND filters.

My guess is you are using something special and expensive, possibly
even something specially designed for dimming, and not bog standard
colour 830 or similar. There are fluorescent lamp controllers which
drive multiple tubes of different colour [temperatures] to create
variable colour temperature output.

I've not tried dimmable CFLs using a normal dimmer, but have Osram dimming
ballasts in the kitchen - and those really don't change colour noticeably.
The other lights are tungsten so give quite a good comparison if dimmed
together.

--
*Rehab is for quitters

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

wrote in message
...


David Hansen wrote:

On Mon, 16 Feb 2009 10:16:16 +0000 someone who may be Peter Scott
wrote this:-

I am now using a conventional dimmer with four low energy dimmable
lamps, and very happy with the range, consistency and colour of the
light.

I wait with interest to see whether the usual suspects come along
and make loud and long complaints about this assertion.

Why?

The OP said he was "very happy". I'm certainly not going to argue that
he's actually putting a brave face on hiding his unhappiness.

Well if the lights were dimmed substantially I guess you wouldn't know how
brave a face he was putting on