I am about to upgrade the lighting in my shop. (hobby, some sales, misc.
It is 21'*31'*9' ceiling. Currently it has 6 fixtures of 2*40w T12. I find
this very poor and must use additional portable lighting for any remotely
detailed type work. Currently no windows.
If I am calculating correctly I am getting about 45lums /sq ft. Most of
what I read (eg Philips) recommends 100 to 300. I don't know what this
I am replacing the existing fixtures (have another use for them) with 15 of
4*32w T8 fixtures. Something like Lithonia troffers and Philips Alto 841
lamps (4100k 86CRI). If I am calculating this correctly that will give me
about 235 lums. I will put 5 on each of 3 switches. I will also add 4
3ft*5ft windows for some natural lights on sunny days.
Does anyone have thoughts on this plan. I really don't know if 235 lums is
in the ballpark. With 3 switches I can have about 80 or 160 or 235 lums.
Should I target a higher or lower level?
My eyeballs are now 49 years old and hope to use this shop for next 15
Thoughts on 4 light fixtures vs more of 2 light fixtures? Lamps types?
I don't know enough about lumens, etc.to answer your
question, but I can give you the benefit of these old eyes
<g>, for what it's worth, which might not be much.
When we moved into this house, the garage (large) had 8 ft.
60W flourescents on a ten foot ceiling. The guy before us
had an appliance repair biz he ran from here. Besides
those 4 fixtures in the garage, there were a bunch of
pieces/parts that would work to make up more assemblies.
Results over the years:
-- They give excellent light in a shop with almost no
shadows possible regardless of how you position anything.
Since each fixture holds 4 of the 8' bulbs, I put switches
in to be able to operate them two at a time. Normal decent
light is available with only the two outside bulbs.
Excellent light with all 4 on. Light colors in the shop
help lots, too. Walls are off-white or antique white -
whatever I had around at the time I painted.
My shop is one car-space, shortened because a room was
built in the back. I have one 4-bulb 8 ft fixture pretty
well centered. The only place the light isn't great is
between some high shelves that are close together.
In addition, I have mounted 4 halogen lights at various
handy locations, and they all switch on/off together since
each also has its own on/off. The combination of
flourescent/halogen seems to give me excellent light for
when I'm doing finishing projects (poly, varnish, about to
experimen t with that oldie but goody shellac).
On my bench I also have an incandescent on a swing-arm
for small, up close work.
Another use I found for the 8 footers is to remove the two
center bulbs and one ballast, and place them close to the
ceiling in our laundry room. The wife really loves it. Did
the same for her sewing room - works great. And by
eliminatin g the center two bulbs you don't take away that
much from available ceiling height, either.
Ballasts for these babies are rather expensive but they
last forever - haven't yet had to replace a replacement.
If your shop is cold, say 45 degrees or less,
flourescents put on a pretty show, but don't give great
light until they get warmed up.
Just my take on life in the shop,
at a minimum, more than "twice as bright" as what you have now.
This is about the difference between a 'partly cloudy' day -- where
the sky is *mostly* clear -- with the sun behind a small (relatively 'thin)
cloud, and the sun -not- behind the cloud.
At the high end, about *seven*times* the current brightness.
This is about the difference between indoors (with 'typical' lighting)
and outdoors on an 'grey' overcast day.
wiring simplification: put the center row on one switch, and put the two
outside rows of lights (combined) on a second switch. only two switches,
and you still have all the combinations of lighting 'density'.
A *lot* depends on the shop layout. You need moderately intense lighting
at places you're doing precision/detail work; Not so much light elsewhere.
five 4' fixtures down a 32' (roughly) dimension means that you'll have only
2' between the end of one fixture and the start of the next one. And roughly
5' between the 'rows' of fixtures.
I'd feel comfortable cutting back to 4 fixtures/row. And maybe even _three_,
with the addition of 'point' lighting (aka 'task lighting') at places where
you need more. 4 fixture rows would give you 64/128/192 lumen options,
where 3 fixture rows would give you 48/96/144 lumen options.
Theoretically, twice the number of 2-tube fixtures will give 'more even'
lighting than the 4-tube fixtures. As a practical matter, the difference
is not noticeable. And the cost/labor savings for the simplifications in
wiring, and the reduced number of fixtures is a definite plus for the
oh boy. THAT's a subject that'll start _long_ tirades.
There's the matter of 'design' of the tube -- T8 vs T12 vs
bulb designs have to be matched to the ballast in the fixture, so this
decision influences the choice of fixtures. And the cost.
there's the matter of the 'color' of the light -- essentially there are
three main variants: 'cool white' (CW), 'daylight white' (DW), ad 'warm
white' (WW). People/flesh-tones look better under warm-white. 'Cool white'
can seem, to some, to have a greenish tinge to it, while 'daylight white'
seems more 'bluish'. It's really a matter of personal preference. And
what kind of lighting you have _elsewhere_; if you want to see colors in
the shop _the_same_way_ they'll appear in the house, for example.
I think you're on the right track. Some thoughts (and what I did in
my old shop and am doing in my new one):
- Make sure all lighting is on seperate breakers from power equipment.
You don't want your lites to go out when something overloads. I
actually have mine on 2 seperate breakers just in case.
- You will be very happy to have some natural lite. I'm putting as
many windows as possible in my new shop.
- Consider mixing Florescent and Incandescent. About half my lite
comes from incandescents. For me it's a more pleasing lite and having
some helps balance out the florescents. Also, if you're selling stuff
or taking pictures it helps since most people have incandescent in
their homes and there's much less color correction needed for
- Wall colors have a huge impact. My walls are light colored knotty
pine T&G (unfinished because I don't want any glare). My ceiling is
painted with outdoor screen paint which is very reflective and helps
to put the light down where I need it and also helps to give a more
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