With the ever increasing electricity prices I'm becoming pretty paranoid
about our electrcity usage. I was planning on having a ceiling full of LV
lights in our new kitchen but how do these compare to standard bulbs.eg .
does a 20W LV bulb use a third of the energy of a standard 60W or is there
some fancy conversion factor I have to apply.
The LV lamps themselves are more efficient than mains lamps.
However, using LV downlighters for general room lighting is
just about the most horrendously inefficient thing you can
do, as you are using the floor as a reflector for the light
to reach most of the areas of the room. It's not uncommon
to find such a room with 600W of lighting which is dimmer
everywhere that matters than it would be with a single 60W
light bulb hanging in the middle.
Forget about using downlighters for general room lighting.
A very effective scheme which is often described here is to
use fluorescent lamps hidden on tops of wall cupboards and
reflecting off a brilliant white ceiling for general lighting,
and under cupboard fluorescent lamps for task lighting on the
worktops. If you have an area with no wall cupboards such as the
sink, using a downlighter or two over that for task lighting
is appropriate use of downlighters. Another option would be
a wall mounted uplighter to light the ceiling in that area.
Summed up perfectly.
If you go for uplighting, stay away from those plaster uplighters,
theyre a pretty poor choice of uplighter, as the bulb is much too close
to the wall.
If you go linear fl, google trough lighting.
If youre determined to have downlighters, there are 2 more efficient
options. One is cfl downlighting.
The other better option is to use 5w filament bulbs instead of 50w,
mouting them relatively shallow so the eye sees the bare filament
directly as well as via the reflectors. This gives the visual effect of
halogens without the power guzzle. Now provide the bulk of the room
lighting with fl or cfl uplighting.
Try replacing them with 35w versions. My kitchen has 8x halogens, and going
from 50w to 35w didn't affect the overall room lighting much but reduced the
overall load by 120w. When these bulbs eventually fail I may give 20w bulbs
a go to see if I can get away with them.
They can be bought pretty cheaply on ebay in 10's.
I might give 'em a whirl, but i`m quite awkward when it comes to
lighting - I prefer all parts of the room to be visible and very well
lit without shadows etc as far as humanly possible - I ended up
splitting the kitchen lighting into a (3x + 4x) and (4x) arrangement so
you didn't get instantly blinded when switching on :-}
My living room only has 4*60W lamps, but they're "regular" incandescant
lamps rather than halogens, so the light distribution is a little better
- plus they're mounted one either side of the chimney breast, with a
pair mounted centrally on the opposite wall - they're on a dimmer, so no
CFLs for me :-}
They're all directional halogens, and not a lot of places get an
appreciable shadow when you're stood in front of a surface compared to
conventional lamps (its a long thin kitchen, so I cross-illuminate from
one fitting back to other areas) - they're set up as two straight rails
of 4 lamps, and the central one is set up as a triangle.
20W is 20W. and is one third of 60W.
LV spots are good only in two ways - they last many times longer than a
conventional bulb, or mains halogen, and they are slightly more
efficient than either of those.
I happen to think that there are far more important things to tackle in
energy terms than what lights you use, myself, but if low consumption is
your target, then only CFL offer any significant advantages.
What you need to bear in mind is luminous efficiency of different
types of lighting, eg fluorescent, halogen.
Also how effectively the light is used makes a big difference, eg
directional LV downlighters pointing down at a dark floor/worktop
won't be very effective for ambient lighting.
For halogen a look at a good lighting catalog will be helpful:
For fluorescent the colour balance (CRI) is important:
A look through the archives of this group will be very useful:
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