Flouresent Shop Lighting, Watts per Square Foot

[Rob Will]

For those that have flouresent lighting in their shop, how many watts per square foot of floor space do you have? Include bench lights if they contribute to the general shop lighting.

Rob

[Travis Porter]

I have 24 4 ft flourescent fixtures with 34 watt bulbs in a 24 x 32 shop so that is 1632 watts in 768 square feet.

FWIW, IMO, the bulbs you use make a difference. I recently changed from the regular cool white bulbs from the BORG to bulbs with a higher CRI (around 82) and a temp of around 5100K. To me, it does not seem near as bright as it was, but the color is definitely better.

[Jerry White]

About 2.2 watts per sq ft and using bright daylight T-8's with white walls and ceilings. Makes for a nice bright room. A little brighter would not hurt....:)

[Steven DeMars]

Shop size = 20' X 22'.

Have 24 twin bulb 4' T-8s with 5000 bulbs.

White ceiling & walls . . .

Yes, it is bright, but so nice . . . .

[Joe Jensen]

28 by 22 foot shop, 48 four foot 40W bulbs. I love it :)

[Randy Meijer]

You can probably get a ballpark figure from this type of poll; but ceiling color, wall color, ceiling height and bulb type will affect the final result. Also existing windows will make a difference. You might want to visit one of the Internet lighting sites and see what they recommend or call your local lighting store.

[Rob Will]

You can probably get a ballpark figure from this type of poll; but ceiling color, wall color, ceiling height and bulb type will affect the final result. Also existing windows will make a difference. You might want to visit one of the Internet lighting sites and see what they recommend or call your local lighting store.

Randy,
I agree. There are way too many unknowns and everybody's situation and needs are different. Having said that I thought it would be interesting to compare notes and see how much energy we are putting toward lighting. In my case with 16' ceilings and 1.75 watts / sq. ft., my shop will be on the low side but probably acceptable. I have room to easily take my shop to 2.9 watts / sq. ft. and keep the lights on a nice planned spacing. (as time and money allow)

Rob

[Dan Forman]

I have 5 2/40 watt fixtures for 400 sq ft. It works pretty well.

Dan

[glenn bradley]

I have under 1 watt per square foot if I count the whole shop. Since I don't work in every nook and cranny a better estimate might be watts covering my "work" areas; about 1 watt per square foot with some task lights here and there. I need more actually. I still have some spots I don't like.

[Cliff Rohrabacher]

I have no idea how many watts I have. I put in lights as I feel the need.

There is no sicience or formula I simply light the shop to my comfort.

[Dick Bringhurst]

Interesting question. Over the years I've changed (incresaed) the lighting to where I "like" it. I just went out and and did the figures. ended up I have 2watts /sf. I guessed it was 3 or more. I use daylight bulbs and have 9ft. ceilings. all white paint. Dick B.

[Ken Fitzgerald]

Rob...........I asked this queston over a year ago. As was advised in your earlier thread, I ordered the article from FWW. In fact, the retired lighting engineer who wrote the article is a member here. Unfortunately I can't remember his name. In the article he takes in account, your age, the height of your ceiling, the size of your shop. He also discusses the type of lights, color index of the lights and the type of starters used. The article was a wealth of information. I used the article to design the lights for my shop. He uses lumens as the reference not watts. Interestingly enough, I calculated the watts based on his design priniciples and it figured out at right at 2 watts based on all the factors he recommended. Good luck with your projects.

[Jim O'Dell]

My shop is 20X24. I will have 28 4 footers when I'm all done. That comes out to 1.98 watt/ft. It's nice and bright right now with 22 bulbs, except for the far corners, which is where the other 3 fixtures are slated to go. I did the same as Ken and ordered the article. The author has posted here on lighting questions before, but it has been a while. I'll try to do a little research and find him again, as I can't remember his name either, and I don't know where my copy of the article is at the moment. Jim.

[Jim O'Dell]

Ok, I found the information. Ken, it was one of your posts that had it. :D



snip....the article is titled "Lighting for the Workshop" by Jack L. Lindsey in the Jan/Feb 2002 FWW. He gives some interesting information on planning your lighting by type...by age...over age 40 he recommends twice as much lighting as pre-age 40.....spacing....recommended configurations etc. Well worth the couple of bucks it cost me to download it! Good luck with your new shop! Enjoy the process ....it's fun! :D

Hope that helps you find the article!. Jim

[Rob Will]

Perhaps an interesting pattern is developing in our poll. So far it appears that about 2/3 of the shops have somewhere around 2 watts / sq. ft.

Then there seems to be a group that has over 3 watts / sq. ft.

That got me to wondering.......of the over 3 watt crowd......how many are using high output fixtures?

Here's why I ask: In order to get 3 watts / sq. ft. with standard bulbs, it would require fixtures to be fairly close together. For example if you had continuous rows of tandem T8 fixtures spaced 5' apart, that would be about 3 watts / sq. ft.

I hope you take the time to vote in our poll so we get a better sample.

Rob

[Jim Becker]

Bump..............

[Jeffrey Makiel]

Rob,
I'm in the 'over 3 watt/sqft' crowd. It's actually around 3.8 watt/sqft.

I use standard T12 4ft flourescent bulbs. However, there is a caveat for me. First, many of my fixtures are cheap shoplights with magnetic ballasts. The bulbs burn bright for about 1 month, then greatly diminish. Second, I don't have a reflective ceiling. Instead, my ceiling is just open floor joists and plywood, (I have a basement shop).

I'm gradually changing out my fixtures for better quality electronic ballasted lights. They are a bit pricey, and I have about 13 more to replace.

cheers, Jeff :)

[Rob Will]

Rob,
I'm in the 'over 3 watt/sqft' crowd. It's actually around 3.8 watt/sqft.
cheers, Jeff :)

I'm starting to wish that I had added a couple higher of categories to that poll.

Rob

[Jim C Bradley]

Hi,
Sorry but when I logged in all of the thread disappeared and I lost all of the names----well all but one, my son, Glenn Bradley.

Anyway my shop is 16 x 20 and I come in at 2.5 watts per sq. ft. I am using dual eight foot fluorescents for general lighting. Some tools have attached auxillary lamps (Drill press, Band saw, and dry grinder). I have a dual halogen work light which I rarely use, however, I am glad to have it. I have a stand for photographic flood lamp (only has 100 watt incandescent in it) which I use fairly frequently.

About a million years ago I took a couple semesters of Illuminating Engineering for the fun of it. A couple weeks ago I threw away my copy of the IES Handbook. Now I wish I had not.

My ceililng is a cathedral type sloping from 9 1/2 feet up to 14 feet. It is all open. Three walls are painted white. The fourth wall is studs and the black paper (translation, "It hasn't been covered yet").

The level of illumination is OK. However, I am sure glad I have supplemental lighting. In class supplemental lighting was continually banged into our heads. Supplemental is the stuff that really lets you see.

My shop is still in the embryo stage. Yes I can use it. No it really violates the "Prime Directive" of everything should be easy to get to and use.

I do not question that I will rearrange the position of the luminaires and I do not question that I will add more lumens.

Jeepers, I don't write in these threads often but I sure do seem to get diarrhea of the keyboard when I do.

Enjoy,
Jim Bradley

PS I have a new 18.5v Black and Decker electric drill battery and charger. If anyone wants it, it is free.

[Mark Neighbors]

In my 14x24 basement (8ft ceiling) shop I have 7 twin 4 foot flourescents, along with three 100 watt incadescent - giving me about 2.5. Considering the dark walls and lack of serious window lighting, I think the 2.5 is about the minimum for my set up.

[Chris Merriam]

I guess my shop falls a little on the dim side. I have an 18x30 basement shop, 8ft white drop ceiling, one finished wall light beige, and 3 concrete walls. I have 4 4ft 2-bulb fixtures, at 32w per bulb, and 8 can lights with 75w halogen bulbs. That puts me at 1.59/sq ft.

The shop is blinding when I walk in from the dim basement, it actually stings my eyes when I first turn the lights on. But once I've been working a bit I would prefer to have more background light. My can lights create too many shadows so I don't really use them much. I had set one over each main work area, but of course if you lean over you create a shadow on your work. I'm thinking of adding another 4ft fixture or two.