John Rumm wrote:
There is some disagreement over on the wiki article :
http://wiki.diyfaq.org.uk/index.php?...nks&oldid=5004
Mostly covered in the Stanley Unwin section he
http://wiki.diyfaq.org.uk/index.php?...26_Switchbanks
On the subject of energy efficiency, NT and I have a difference of opinion:
The words as I left them in the intro said:
"The pros and cons of switchbank lighting versus dimmer control will
vary depending on use patterns. For users who typically use maximum
brightness, then neither technique will save much energy, although
dimming will have a slight edge since it will tend to extend bulb life a
little (and hence re-lamping costs) by virtue of the slight reduction in
maximum brightness that is usually enforced.
For users who routinely use less than full brightness illumination, the
energy saving potential of a switchbank is far greater. "
The new wording says:
"The pros and cons of switchbank lighting versus dimmer control will
vary depending on use patterns. For users who nearly always use maximum
brightness, neither technique will save much energy.
Dimmers at full brightness have a slight energy efficiency disadvantage
since the triac voltage drop will run the lamps at very slightly lower
rms voltage and efficiency, but the amount of the effect is trivial.
This does also extend lamp life by a trivial amount, with a tiny
consequent saving on bulb manufacturing energy, but this is much smaller
in size than the energy efficiency reduction due to operating at
slightly lower rms voltage. In all these effects are trivial. "
To me this seems somewhat complex and perhaps a little obtuse.
Any thoughts on better wording?
I think the effects of dimmers at full brightness is sufficiently
trivial
not to need addressing at all. I responded on that only because you
introduced the question of its effects.
You seem not to realise that there is any way a dimmer
can increase electricity consumption compared to the other
options. In fact there are a few ways it sometimes occurs.
A. Usually what people do when they want lower lighting level is
switch the main light(s) off and use other lower power lights. This
means those lights run at max energy efficiency. Using a dimmer
instead runs more lights at much reduced efficiency, thus eating
more power for a given lighting level compared to the other real
world options. Thus fitting a dimmer for people that already do this
will increase their energy use, not reduce it.
B. Dimmers preclude use of CFLs. Some people do and will use
CFLs, so again dimmers sometimes force filament lamp use with
their 3 or more times as much energy use.
C. Since the ideal lighting arrangement provides at least 3 levels:
standard, reduced for comfort, and higher brightness for detailed
cleaning etc, some people who use a dimmer will fit enough wattage
to cater for max output and spend a lot of time running them slightly
dimmed. Electricity consumption rises significantly due to this,
as was explained until you edited it out.
To assume that fitting a dimmer will reduce your energy use is just
plain wrong. If we're going to put the time into writing articles,
really
they need to have some degree of expertise to them rather than
being repetition of popular notions.
- On which matter I'm guilty when it comes to the sand article.
No-one seems to have raised the bar on that one yet.
http://www.wiki.diyfaq.org.uk/index.php?title=Sand
2. If I understand you you think reducing energy efficiency with a
1.5v drop will reduce household energy consumption, when IRL
sometimes people will accept lower use and sometimes they will
say no, too dim and put bigger bulbs in. You're not going to lower
average power consumption by reducing energy efficiency. The
energy saved by the trivial extension of bulb life does not make up
for this, as you'd know if you understood why GLS lighting has
1000hr mean life.
TBH the article needs a good rearrangement so that the issues
can fit the heading framework sensibly, and I think for once you
could do with being a bit clearer on this subject before editing this
one. I can quite accept the article needs work, thats how wikis go,
but removing valid content that perhaps needs wording more clearly
and inserting common misunderstandings isnt helping us to get it
there.
NT