We are told that halogen bulbs produce twice as much light as an ordinary
bulb for the same power consumption (50 watt halogen = 100 watt ordinary)
we can expect to pay about 5 times as much for halogen bulb for this benefit
I have often treated this claim with much sceptisism since i noticed halogen
cycle lamp bulbs claiming the same were actually double the wattage of
ordinary vacuum bulb and gobbling up batteries in much less than half the
time (no different from doubling the wattage of std vacuum bulb) ????
Anyway - after a new kitchen refit - i just replaced 3 x 100 watt vacuum
spots - with 3 x 50 watt halogen spots - i think it's fair to say that far
from their claim of being 'as' bright - they are not even half as bright -
the kitchen looks positively dull
I will be able to confirm this since i bought another 3 x 50 watt halogen
spot - and i intend to take these out and mount them with the other cluster
to make 6 x 50 watt halogen cluster
Which leave the questions:
How did halogen bulbs make it onto the market?
Why do people buy them?
Who is We? And who is telling We?
That information on a like-for-like swap basis is incorrect.
Yes, indeed. However, that's nothing to do with the lamps
themselves -- it's because the lighting is inappropriate for the
purpose for which it's being used. The halogens probably are slightly
brighter, but because they have more accurate beam control and less
light spillage, they will only be lighting up a patch underneath
them. The light level in the rest of the kitchen now depends largely
on the reflectivity of the surface with those light patches, which
is typically very low. With your previous reflector lamps, the beam
control is bad, so light spills all over the place, and gives you a
better lighting level in the rest of the room. Both types of light
are inappropriate for general lighting in a room, one more so that
the other. If you want a room lit well, you need to design (or have
designed for you) a auitable lighting scheme.
Halogens work well when used correctly.
Using halogen spotlamps for general lighting is usually inappropriate
and hence gives poor results in terms of low lighting level and/or high
Most people haven't got a clue how to design effective lighting schemes,
and don't realise they don't have a clue. Also, those lights are usually
dirt cheap initial cost.
[email address is not usable -- followup in the newsgroup]
I think Andrew is exactly right. Halogen bulbs run at a higher temperature,
they can do this because the quartz of the glass allows it without breaking.
The halogen gas is better for longevity than the vacuum - you can't produce
a perfect vacuum anyway
thus the gas left in will oxidise at high temperatures, deposit oxides on
the glass and
dim the output. So Halogens produce a whiter light, "brighter" if you like,
which is great for throwing
the light longer distances.
We did the same - put sunken spots in the kitchen but specifically where
they were needed. Typically,
normal lamps are usually placed in the centre of a room and then you stand
in your own shadow when working at the surfaces
or the sink. Equally, large lamps placed at the periphery of a ceiling look
pretty daft. The spots ( two over the walkway and 6
over the surfaces ) work brilliantly, giving light to the working area.
However, they need to be close enough to each other
such that some light overlaps the next spot, which avoids shadowing of your
hands and the work. They need to be placed
close to the wall so that some of the light hits the wall and reflects
downwards too. Even with these 8 x 50 watts
the impression remains that our kitchen is dull, but when actually working
at the surfaces all is well.
Halogens can be designed to run at a slightly higher temperature,
or to have a longer life. In the domestic/retail sector, they are
normally designed with longer life, because people won't by a lamp
which costs 5-10 times as much and only has the same life, regardless
of its other properties.
Ordinary filament light bulbs are gas filled with nitrogen, to
slow down the rate of evaporation of the filamant. The only
vacuum bulbs are the low powered mains ones (e.g. 25W and below)
and the tubular filament lamps, all of which are horribly
Halogen lamps usually have smaller/shorter filaments than
conventional lamps. The smaller light source makes it possible
to design the lamp optics to produce a more controlled beam
with less light spill off-beam, and where desired, a narrower
Before you start thinking about spotlamps, you need good general
lighting in a kitchen, covering everywhere. A very effective way
to do this if you have wall cupboards is to use fluorescent tubes
hidden on top of the cupboards, lighting up a brilliant white ceiling.
The indirect light reflected from the ceiling gives you a good level
of illumination all around with no shadows. For intricate work, such
as food preparation, washing up, motorcycle engine stripdown, etc,
you will probably benefit from task lighting providing a locally
enhanced lighting level at the worktops. Under cupboard fluorescents
are excellent for this. Spotlamps could be used but won't give you
shadowless even lighting. Finally, if you have any features or display
areas which would benefit from highlighting, that's what spotlamps
are for -- it's called accent lighting. Given the good general lighting
already present, you should only need something of the order 10-20W,
and not 50W spots. Have the different types of lighting separately
switched, which gives scope for boosting outdoor daylight without
having to turn on everything, and different mood settings in the
evening, e.g. by switching off the general lighting and just leaving
accent and/or worktop lighting on.
The last two kitchens I've done have had no lights on the ceiling at
all. It's a remarkably useless place to have lights in a kitchen
(unless you have an island or table).
[email address is not usable -- followup in the newsgroup]
We only have one cupboard, so that wouldn't be an option in our case.
Under cupboard fluorescents
Well I must disagree - if the sunken spots are close enough together as ours
very low shadow is obtained and even lighting across the work surfaces,
due to the spots being close to the wall.
Finally, if you have any features or display
Now that's a good idea, I must say we didn't think of directional spots
as well. There are a few features that may benefit from some further light
such as the Aga
and the plate display.
When I changed from a 0.4A @ 6V tungsten (vacuum/ inert) to 0.4A @ 6V
halogen headlight on my bicycle about 15 years ago, I found the new
light to be substantially better. I didn't do any measurements (or
recall any `twice as much light' claims) but my subjective experience
was that there was much more and whiter light. Yet the lamps had the
same power rating and the dynamo, for the sake of brevity, was not
capable of putting a different amount of power through them. The
lamps had a much longer MTBF, too, which was counterintuitive. To
this day, I'm sticking with halogen until a more efficient alternative
shows up which can get close to matching the colour rendering ability
My kitchen and bathroom have tungsten spot lamps as downlighters for
general lighting. The `spot' is about 110 degrees wide so the type
and distribution of the light is not far off that of GLS. All of the
halogen lamps I've seen have a much narrower beam and for that reason
I wouldn't dream of using them as replacements for the tungsten lamps.
I'd wager that if you lay on the floor directly in line with your
halogen lamps, you'd find them very bright. As Andrew Gabriel says,
that's only useful for general lighting if you point them at something
... Fools and money? Or for people using them in applications where a
narrow beam is called for. I've never been able to understand why
someone doesn't make a genuinely wide beam version of them (much wider
than the ones currently described as `flood' lamps), though.
What's the point of all these poncy lights? They're expensive to buy, fit
and run. The illumination quality is also dubious. I have a decent sized
kitchen and all I have is a 5' fluorescent on the ceiling, a small
fluorescent under a worktop and a light on the cooker. The overall
illumination is perfectly adequate and cheap to run, unless you want to
perform a surgical operation on the kitchen table!
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