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09-04-2008, 12:28 AM #1
lighting advice for 400 sq ft shop
Have a new 20x20 shop area to light, with 9 foot ceilings.
What's the best approach for this? I've seen some other threads not to long ago, but they were for high bay spaces.
I don't like T5 ballast buzz in other shop, which also has inadequate lighting. Should I design to watts or lumens per square foot?
09-04-2008, 12:51 AM #2
This might be the thread in question...
Shop lighting suggestions
A 20x20 is similar to a double-car garage. I would think about 6pc x 8 foot T8 fixtures would have it simply brilliant inside if you had white-walls. This would draw 6A total on 120vac. (~768 watts) Keep in mind there's a tradeoff in the color temp (deg Kelvin) of the lamps. The general tradeoff is color perception vs. detail perception from what I read.
Are you sure you aren't thinking of T12 mag-ballast buzz?
09-04-2008, 01:51 AM #3
My 2 car garage (the actual garage - 440sq ft) has 5 - 2-bulb 4' T12 fixtures and no ceiling right now (no reflection off the roof as the fixtures are suspended via the rafters). It's kinda dark, but not bad. The ballasts do buzz.
I went with T8's in the shop, higher ceiling (11' vs 10) and painted white. I'm using 24W energy saver bulbs in 4 - 4-bulb 4' fixtures (roughly 600sq ft lit by these 4 fixtures). It's bright, but not harsh. I do wish I'd gone with full strength 32W bulbs. The ballasts don't buzz much, but once the machines are running you'd never notice it. First thing I do is turn the stereo on, so the noise is rarely even heard.
If prices ever drop, I'll be installing dome/tube skylights in the shop. The amount of light those tubes transmit is astounding. My grandma has one in her bathroom with no windows and I catch myself reaching for the light switch (to turn it off) every time I'm there.
Last edited by Jim Shaper; 09-04-2008 at 03:19 PM. Reason: I screwed up on the bulb size. Not t5's like I originally posted.
09-04-2008, 02:04 AM #4
T5's shouldnt make any noise, at least not with a good ballast. I have a 4 lamp 54W T5HO fixture above my pool table and it is silent. I also used to use 6 - 54 watt lamps in my aquarium and those were silent as well. These were Advance and Sylvania ballasts.
09-04-2008, 02:10 AM #5
I can still hear them. I'm running Phillips bulbs with Lithonia fixtures. Maybe it's just the bulb, but they do make a noise.
09-04-2008, 08:07 AM #6
I am at the tail end of moving and setting up my shop at a new house. My previous shop had an 8' ceiling, 23 x 25' in area, and lit with 4, 8' T12 HO fixtures with magnetic ballasts. Lots of buzz, shadows, and noticeable heat output on warm days. The arrangement had a total of 880 watts of bulbs, and produced 67,000 lumens of output. My new shop is 20 x 22', with 9 1/2' ceiling (yes, an addition is in the plans!). I went with 8, 8' T8 fixtures with electronic ballasts, each running 4, 4' bulbs. I shopped around a bit for bulbs, and settled on phillips 4100K, 25W bulbs from Home Depot. They cost a bit more, but had the highest Lumen per watt ratio I could find. They also use 7 watts less energy per bulb, and when you are running 32 bulbs, it does add up. My new lighting setup uses 800 watts of energy, and produces 100,700 Lumens of light output!
I must say, it literally hurt to lay down $500 for lighting a two car garage, but that pain instantly subsided the first time I flipped the switches! Gone is the buzz, and the shadows are almost non existent. I would absolutely recommend this setup for any shop.
09-04-2008, 08:12 AM #7
I like incandesant blubs and have them 8' apart in the garage/shop. I use 100 watt daylight bulbs.
09-04-2008, 08:36 AM #8
I am using about 1400 watts of flourescent lighting in my garage that is about the same floor space as your shop. It is a combination of 4 foot and 8 foot fixtures. Most of it is area lighting. There are 3 fixtures located over specific machines/work areas to provide adequate work light.
You might be able to get away with less wattage if you have a white ceiling (mine is open truss-work, so poor reflectivity) and white walls (mine are unfinished sheathing ply and studs).
I feel that money spent on good lighting is well worth it as it positively affects your attitude.
To save on operating costs, wire the lighting banks to cover different zones (parts of the room). That way, if lighting the entire place is not needed, you can select just the portion you need. Mine is 3 zones: right, center, and left side of garage. Generally I only need one or two zones at a time.
Avoid the watt-saver tubes. You need a good light just to see if they are working......
09-04-2008, 09:50 AM #9
According to the folks at Home Depot four 4' flourescent bulbs per 100 sq/ft for close work so I would use a minimum of 4 and add if not enough light in specfic areas
09-04-2008, 05:00 PM #10
Two points. First - ballasts have a noise rating. The ones rated to be quiet are in fact quiet. They generally cost more tho.... Second - you can't have too much installed light. If you plan ahead, you can always use part of your lighting system. I think of it something like heating zones. I have an 1100 square foot shop with 62 40 watt t8 tubes. Tha is over 2500 watts of consumption if they are all on. Most of the time I am working in one area and use less than a third of the lights. Plan the wiring/switching ahead!!!
09-04-2008, 05:50 PM #11
I think all of the advice posted here sounds good.
Here is my limited recent experience with installing lighting: For an 8 X 12 shed (about 1/4 the size of your space, I used a single 2-bulb T9 fixture, with a pair of 4-ft long 32-watt fluorescent bulbs. So that is 64 watts. FYI, here is a pic of the shed, lit with just one fixture on a low "ceiling:"
Product review: Lifetime brand storage sheds
Without making measurements, I think that a shop space would do well with about twice that amount of lighting. So that means two of these fixtures, or about 125 watts per 100 square feet. Thus, I estimate that your shop could be well lit with 8 fixtures, or 500 watts of fluorescent lights. (This is approximately consistent with Matt's first suggestion for ~768 watts). But I also like Bruce's idea of having extra lighting available for when you might want it.
To get the light fixture, I went to the Orchard Supply Hardware store on Ashby Avenue in Berkeley. To get low noise, make sure you buy ones that are labelled as "electronic ballast." For bulbs, I prefer the ones that are marketed for "kitchen and bath use" (slightly warmer color), rather than the ones that are marketed for "shop" use. I think the brand of fixture I got was GE or some other recognizable name. The fixture was reasonably cheap, I think around $30.
I think that eight 2-bulb fixtures should light your shop nicely. Task lighting is helpful for individual machines or work areas.
09-04-2008, 07:23 PM #12
One of my shops is 24 x 24 ft and is area illuminated by 14 dual 40W 4 ft tube flourescent fixtures wired in three switched zones as some have suggested above. The shop has a 8 ft high white ceiling. Additionally, each individual fixture is equipped with a pull chain on-off switch so the entire shop can be customized to light the zone I happen to be working in. Also, each machine and work station has a work light. I set this up over 25 years ago and have never regretted it. A well illuminated shadow free work zone is not a luxury, it's a necessity for my work.
09-04-2008, 11:04 PM #13
An added point on noise. Get A rated ballasts. They are quietest. Not all electronic ballasts are A rated. Be sure and get the A noise rating.
09-04-2008, 11:59 PM #14
When I built a woodshop (about 300 sf) a couple of years ago I went with recessed cannisters with fluorescent flood lamps in them. Nice and bright, they don't put out a lot of heat during the summer but still warm up quickly in the winter. I decided on the recessed lights because I have whacked the 4 tube hanging fixtures in the other shop a couple of times and it is a mess to clean up. One thing to watch with the floods is the color is a little weird, so if I am trying to match a finish color (or tracing wires), I break out a portable halogen full spectrum worklight to help. I am going to build a new shop next year and plan on doing the same thing in it because it has worked so well.
09-05-2008, 12:18 AM #15
Thanks for all the suggestions... very helpful.
I said I had T5 in other shop, but that was a typo -- I had T8.
With respect to noise, when I bought the T8's, I didn't research details extensively. I had heard basically two pieces of advice: they must be electronic ballasts, and don't buy cheap ones. So I bought the most expensive electronic T8 fixtures/ballasts at Home Depot. But they make a very noticeable (to me) hum. When machines are running I of course don't notice, but when nothing else is running, I really hate the buzz, even though pretty mild. When I stop to think, or draw, or do some math, or just kick back and zone out, it's peaceful to have no buzzing.
I'll look for A rated ballasts.
09-05-2008, 09:12 AM #16
I've got the Lithonia T-8 fixtures from Home Depot, the ballasts are Class A Sound rated made by Advance, and I can hear them fine. If some of the folks who say theirs are silent can post a manufacturer's name and model I'd appreciate it!
09-05-2008, 11:29 AM #17
I ordered my ballasts through a local electrical supply place. When I ordered, I got an agreement from the store to replace the ballasts if they made noise. We discussed the A rating, but I also took the extra precaution because I hate ballast noise. Everything was fine when I tested the first one (before installation). But here is the suprise - mine are from Advance as well!! So now I don't even trust the A rating. I guess you have to get a sample and test it!!!
09-05-2008, 09:48 PM #18
Ck out Lithonia
I am outfitting my 28x150' shop with the Lithonia T5HO 6 lamp I-Beam fixtures. I didn't know how many to purchase so I called a distributor I found on the Lithonia website. They put the parameters of my shop in some kind of a lighting computer program and determined how many fixtures and the layout. Pretty neat actually. The 6 lamp might be overkill for your shop but maybe a distributor could suggest someting. There was no charge for the layout.
09-05-2008, 11:01 PM #19
My shop is a total of 3000 sq ft divided into two roughly equal rooms. I painted one room white, floor to ceiling, including the ceiling, and installed fluorescent lights. The other side stayed the yellow the previous occupants painted it with six 300 W incandescent lamps. One day I tried to assemble a machine in the latter room and was bewildered by my inability to fit parts together. Then I realized that working in the almost shadow free other room, I had gotten out of the habit of keeping my hands from shadowing the work. A dollar in white paint is worth at least ten in lamps. Also, you don't want concentrated light sources like hi bay lamps because they will be so close that they will be very annoying.