I have two chandeliers with 5 x 40 w and 3 x 60 w golf-ball tungsten bulbs
at the moment. They are both on dimmer switches. The only place I can get
replacement bulbs is the corner shop that buys containers loads from China.
My first option for replacement seems to be halogen, which are expensive
and why they are supposed to be more ecologically friendly I don't know as
the wattage will surely be the same?
Second is energy-saving, but they are even more expensive and would 'show'
above the glass light-shades - and not work with the dimmer switch.
I have not even looked into LEDs as I know nothing about them in this
Halogens can be run hotter which pushes the peak of the radiation
profile more towards the visible (for ordinary tungstens, the peak is in
the infra-red). So more of the energy input comes out as visible light.
"That excessive bail ought not to be required, nor excessive fines imposed,
Just to add, they do actually use less energy because the sell 18W
halogen for 25W replacement and so on.
Any energy saving turn to shit however when the lamps are dimmed and not
used at highest efficiency super hot mode.
I'm saying that you lose the efficiency benefit of halogen when they are
not running white hot, they just become normal lamps.
Actually, because of their high temperature optimisation, they may
become less efficient than normal GLS when not in the zone (this is my
suspicion/theory, not backed by objective evidence).
It is well known that 50% dimmed GLS lamps still use 75% of rated power
with efficiency getting progressively worse the more the lamp is dimmed.
End result is that it's not energy friendly to have a 380W populated
fitting mostly running dimmed to 1/4 brightness as it would probably
still consume about 190W.
Relative efficiency experiments of dimmed halogen vs dimmed GLS left as
an exercise for those with the time.
I'd assume if you dim a lamp you are no longer interested in its maximum
output or efficiency. Think everyone knows the actual efficiency drops
when a filament lamp is dimmed - but then so does the current consumption.
*I was once a millionaire but my mom gave away my baseball cards
Dave Plowman email@example.com London SW
Not more electricity but you would be better off missing one lamp out
entirely than dimming several of them at once. Lumens per watt goes down
radically as the filament temperature decreases.
Not only that but when dimmed you compromise the internal halogen based
recycling chemistry that prevents the envelope from going dark with
evaporated tungsten from the filament.
The lamp will dim OK on a dimmer but it doesn't do it much good. I think
some of the harm can be undone by running them hot again at full power.
The latest generation of led lamps are getting to be very good but are
still fairly expensive at present. Try one out of Amazon and see if it
will do what you want. I have been caught out by one that was nominally
60W equivalent being too bright for the intended position!
200W plus 180 W = 380 W when flat out, roughly 22p/6hr evening
(10p/unit(*)) roughly. £80 odd quid/year.
No halogens have a lower (75% ish) wattage for a similar light
output. Halogens are dimmable but ideally you don't want to run them
significantly dimmed for long periods as the tungsten cycle within
the capsule doesn't work properly and the tungsten from the filament
gets deposited on the inside of the capsule reducing light output and
shortening their life. The colour temperature is also higher than
ordinary incandescant so the light may appear harsh.
You can get dimmable energy saving Compact Flourescent Lamp (CFL).
The extra cost is offset by the lower power consumption and longer
Your total power consumption with CFLs would be around 100 W. Based
on 9 W CFL for the 40's and 15 W for the 60's. A CFL upright in an
open fitting will probably last 8000 hrs or longer, a good 4 times
longer than most ordinary tungsten bulbs using 1/4 the energy. CFL
tend to be "soft start" ie they take a minute or two to get to full
brightness, for somewhere were they are on for long periods this
isn't an issue IMHO. The colour temperature can be a bit "odd" but
modern ones are much better than ones from 10 years ago.
The big problem with most LED lamps so far is that they are
directional, spot lights, downlighters etc. There are a few "corn
cob" types about that might be OK in a chandelier or see the "New
style LED Light Bulb" thread.
Dimming is again a problem having said that do you really *use* the
dimmer to adjust light levels or is it just a "set and forget"? If
the former you could probably select your required light level by
selecting suitable output bulbs and run them without the dimmer.
Mentioned here as LED struggles to get decent light levels but if you
don't need the flat out light level of what you have. LED power
consumption is a bit lower than CFL but they cost more.
Bottom line, the ordinary tungsten is expensive to run and I expect
you are changing a bulb around every 4 to 6 weeks. Halogen will make
some savings, I've not done the calculations of power saved v cost v
life for halogen. Halogens cost a bit more but I think have a similar
life compared to ordinary.
CFL will almost ceratinly end up in "profit".
LED probably will as well but will be very dependant on the capital
cost of the lamps. Life should be longer than CFL, like CFL the
electronics suffer from overheating in some enclosed fittings.
The only real way to be moderately sure is to build a spreadsheet to
model the various lamps and their total overall costs. In your
situation I'd take a good look at LED and be prepared to pay quite a
bit for a quality, known brand, bulb on the basis of greatest energy
saving and life. The fall back would be CFL.
On Sun, 07 Jul 2013 11:13:06 +0100, Dave Liquorice wrote:
I replaced every possible tungsten lamp in the house with LED, nearly a year ago. I can't recall the exact
figures, but something like 1kW of lighting was reduced to less than 100W. Specifically, in the kitchen/utility
room 430W of halogens was replaced by 36W of LED, and it's a brighter room than before.
The claimed life of the LEDs lies between 15000 and 30000 hours. Over that period alone replacement
tungstens will cost about the same as the LED they replace, leaving massive gains on electricity consumption. I
estimate I'll save about £1000 over the life of the LEDs. Buying cheap filament lamps that have a high power
consumption is a no-no. Do the capital investment and reap the financial benefits.
Come the power cuts of 2015, a 900W inverter generator will run the lights, TV, fridge-freezer, and central
heating...while my neighbours shiver in the dark.
 There are two fittings flush to the ceiling that take a G9 lamp; I can't yet find an LED replacement for these
that has the 800-lumen output of the 43W Xenon tungsten currently fitted, so for the time being these will stay.
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