LED lights in shop

Didn't want to hijack Hay Hay's thread, concerning LED lights. Big sale on them at Home Desperate, and I'm adding on to my shop- 24' X 40', about a 9 foot ceiling (yeah, I know that's low, but I'm going to insulate and heat it, and I've got another high-ceiling shop with an overhead I-beam and sliding winch when needed for the heavy-duty stuff. And as I get older, there will be less and less "heavy stuff". LOL).

So what spec/model, and how many, LED's do I need for such a lash-up? What "key words" am I looking for on the description? I've got 8 foot HE fluorescents in the old shop, but they're getting hard to find, and increasingly expensive.

Thanks for any input.

Got about that same area in my garage.I put in 4 30K lume fixtures in place of the keyless. Really brightened it up.

A couple ways to go about it, but what you want is a "lumens" comparison. Lumens is the amount of light being produced. This is an important number when going LED since the wattage is much lower with LED.

You can Google the lumens output of the lamps you have, multiply that number by the number of lamps in the area, you get the total lumens. If you are happy with the existing light level, just do the same with the replacement lighting.

Or, if you're replacing the fixtures, look at the engineering specs for the fixtures. There will be drawings showing the various heights, distances between fixtures, overlap, light levels, etc.

If you decide to replace the fixtures, reflector type fixtures help get the light down where it needs to be, and keeps the lamps cleaner.

I have a 40x60 work and light it with 6 LED security lights giving off 3,100 lumems each and mounted 12 foot in the air. I have used t8 cold start fixtures( not led) over work bench and lathe.

Its IMPOSSIBLE to accurately tell you how many fixtures/bulbs you may need without knowing a whole ton of facts such as ceiling height, height above work space you wish to illuminate, square feet, color and reflectance of ceiling and floor, lumens of light per fixture etc. etc. etc. One zonal cavity method formula that may help you is that Footcandles = Lumens x Coefficient of Utilization divided by Area. THE HARDEST PART IS TO CALCULATE THE CU as that depends on height and colors and reflectance etc. In an office with 8 ft white ceilings and good fixtures, the CU may be high like over 0.7, however in a dark floor and ceiling shop with high ceilings it may 0.4 or less.

As an example, if you wanted say 50 foot candles on your workbench (a decent light level),,,,,,,,,,had an area lets use 1000 sq ft (20 x 50),,,,,,,,,,,,,,each light bulb produced say 1500 lumens (like a 100 watt incandescent),,,,,,,,,,guess at CU is 0.5,,,,,,,,,,,, HOW MANY BULBS ARE NEEDED????

50 = X lumens x 0.5/1000,,,,,,,,,,,,50,000 = .5X,,,,,,,,,,,,,,,x = 100,000,,,,,,,,,,,if each bulb produced 1500 lumens,,,,,,,,,,,,,100,000/1500 = 67 light bulbs IF MY MATH IS RIGHT NO WARRANTY LOL

NOTE if the LED is rated 100 incandescent watt equivalent (but it uses far less watts) that could equal around 1500 lumens of light for each bulb. Still the CU depends on the fixture in which its enclosed and its color and reflectance and ceiling and floor and reflectance etc etc ITS EASY IF I HAD ALL THE DATA

TO GIVE YOU AN IDEA OF ILLUMINATION LEVELS: In a drafting room you may require say 100 footcandles of illumination, while an outdoor parking lot may have only 5 footcandles, while on a bright sunny summer day there could be 10,000 footcandles outdoors

DISCLAIMER It was nearly 40 years ago I attended a week long lighting seminar at GE's NELA Park in Cleveland Ohio and Ive been retired as an engineer like 24 years SO NO WARRANTY AND DONT ANYONE HAVE A CALF IF THIS IS ALL WRONG its just my best effort to provide some insight and theory of how to compute how many lights/fixtures/bulbs may be required but it takes the heights and colors and reflectance and other info to give an accurate answer WHICH THIS IS NOT

John T

I would like to add a little. With LED bulbs you can get several colors of output. Your good old edison bulbs that get nice and hot are around 3200 to 3400 degrees kelvin. This is that nice orange light that you have known since the days of candles and kerosene lamps. I prefer the 6000 degree bulbs that are the same color as DAY light. You can see so much detail and much sharper looking. Most of the depot stores have that little display so you can see the difference in the colors. I have them in my kitchen overhead fixture and they are pretty bright till you let your eyeballs readjust for a few seconds. After that you can really see stuff very well. Let us know.

There must be a time and a place for 6000?K (or 5700?K) LED lamps, but I have a hard time agreeing with you that that HORRIBLE eye-irritating BLUE light is the color of "daylight"!

(Maybe in the dead of winter in the middle of a HOWLING ground blizzard when the snow in the air filters out all but HARSH blue light???)

I like the "warm" ones over the daylight.

My shop has always been rather dark. I've used 100w incandesents, 4ft floresents, and never had as good results as a 60w equivalent daylight led. That's my experience yours may vary.

At a minimum I would use 10 keyless lamp holders and 100 watt equivalent LED bulbs in the 5k color. Anything more than that will make life just that much easier. The 10 bulbs will give you low cost and ok working light. There are some LED fixtures that look like 2 bulb 4'fluorescent fixtures that are reasonably priced and work well. The one problem is that no matter what light you use, sooner or later you will be working under the hood of your car or underneath a tractor, and then there will be a shadow and you will need a trouble light or something similar. John T probably has as good of a "recipe" for lighting as anyone. Lighting is like building size, no one ever built a shop too big or put too many lights in it.

Thanks, everybody. I did some cackelatin' down at Home Despot, and found that the 8' cold-start tubes are 8,800 lumens, and the highest LED I could find was 1000. My present 30 X 35 shop has 12 tubes, and at that rate, I come up with an ungodly number of LED lights, like John T did. Maybe those ol' tubes aren't so bad, after all. . .

I bought drop in replacement 8 foot LED lights off Amazon, Wire around ballast, Just as bright as the HO bulbs I took out. Not sure what the specs are , will try to find them . In fact , a couple fixture I used only one 8 ft LED instead of two .

Indeed the actual light illumination level rating is in LUMENS and that's a number you ought to be able to find when buying bulbs/fixtures. If your bottom line is now X footcandles and you want to replicate it YOU NEED THE SAME LUMENS YOU HAVE NOW. Then Footcanles = Lumens X CU/square feet.

John T

Bryan, I would be very interested in a "drop in replacement" for the HO tubes I have in the "old" shop. Let me know if you find the source.

We went through a huge relamp project at work this Spring- they replaced the overhead lighting in the main building with LED fixtures. The old ones were the yellowish sodium bulbs, the new ones a three-section LED circle. I understand each section can be replaced independently. Of course, these are about a hundred feet up in some areas, and quite warm in the summer (130f+). Supposedly the new light is three times brighter, I would agree there. These are 600V fixtures, not many of us can support them, but we hear of plans to relamp the 130V units elsewhere in the plant, I'll update if info becomes available.