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Paul M. Eldridge Paul M. Eldridge is offline
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Default Incandescent lighting for high ceiling

On Sun, 10 Feb 2008 10:12:25 -0800 (PST), "
wrote:

I have a room in our office that has a high ceiling (28' floor to
underside of ceiling) and it has industrial HID lighting that is
bright but takes a long time to turn on. It is gives out a glaring
white light.

We want to give the room a more cozy feeling and we don't need it that
bright. Does anyone know of any Incandescent can lighting that we can
hang from the ceiling? We prefer it takes bigger wattage bulbs, such
as the PAR38 and etc blubs).

Some pics of our room can be found at www.sopmedia.com/lighting/image1.jpg
and image2.jpg. We are looking for the can lighting in
www.sopmedia.com/lighting/image3.jpg.

Any suggestions would be much appreciated!

Thanks


In your case, incandescent or halogen lighting would be a bad fit
given its relatively poor efficiency (measured in lumens per watt) and
the height of your ceiling -- remember, light output falls at the
square of the distance, so a lamp suspended at 28 ft. is only one
quarter as bright as one at 14 ft. and one-sixteenth as bright as one
at 7 ft.

Watt for watt, metal halide lighting is four to five times more energy
efficient than halogen and rated life, in most cases, is five to ten
times longer. Thus, one of the questions you must ask yourself is how
do I change these lamps when they burn out? Do you have convenient
access to a man lift and are there any obstructions at floor level
that would make it difficult to manevour it about? Also, assuming
you're located in North America, do you have a 120-volt power supply
to serve these lamps? Most HID fixtures operate at 277-volts in the
U.S. and 347-volts in Canada, so you may not be able to utilize your
existing wiring and switching, and pulling new wiring can be
prohibitively expensive.

Personally, I would recommend you go with a high bay T8 or T5 fixture.
You can easily swap these one for one with your existing HIDs (just
make sure the ballasts are compatible with your supply voltage). The
big advantage is that they're even more energy efficient than your
current system and typically draw less power, with a corresponding
reduction in your air conditioning load. In addition, they can be
switched on and off at will and even hooked up to automatic dimming
controls and occupancy sensors. The light quality would be notably
better (e.g., a CRI of 86 versus 65 or 70 for traditional metal
halide); there would be better light distribution and far less glare;
no flicker and, most significantly, no annoying ballast hum. As an
added bonus, lamp life can be as long as 40,000 hours versus 15,000 to
20,000 for HID, and lumen maintenance would be vastly superior (at end
of life, the amount of light produced by a HID lamp is generally half
that of its initial rating; by comparison, a good quality T8 can still
produce 97% of its original output). Plus, you have a wide range of
colour temperatures from which to choose, from 2,700K at the low end
(incandescent like), to 3,000K (similar to halogen), 3,500K (neutral
to slightly warm), 4,100 (cool white), 5,000K (daylight) and even
6,500K and 8,000K. Generally speaking, I find 5,000K a good choice in
commercial environments, especially if you're located in a cooling
dominate climate.

Cheers,
Paul