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LED Shop Lighting Upgrade

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Forum topic by JBrow posted 01-06-2016 02:23 AM 1344 views 1 time favorited 21 replies Add to Favorites Watch
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JBrow

818 posts in 385 days


01-06-2016 02:23 AM

Problem. In August 2015, I purchased the CV 1800 Cyclone Dust Collector. Therefore installation of 6” duct work throughout my 2 car attached garage workshop was needed. The workshop is about 450 square feet with an 8’ 5” high ceiling. Since there are trusses running every which way, installing duct work in the attic was not an option. The duct work had to go on the ceiling.

There were 14 2-tube T-12 florescent light fixtures (the really cheap $10 fixtures with magnetic ballasts bought 20 years ago) mounted in rows with three or four 4-foot fixtures in a row. The rows were mounted 4 feet apart. Options for providing a duct work path were 1) relocate some light fixtures to make way for the duct work, 2) reconfigure the lights completely, or 3) replace them. These lights performed ok, but struggled in the winter when the shop was cooler. They also provided adequate light in the workshop and were probably about as efficient as one could get when purchased.

Attempting to derive specifications for the 20 year old fixtures is problematic at best. I estimate that power consumption, including that of the original magnetic ballasts, is about 150 – 170 watts per fixture, including the two 4’ 40 watt lamps. The Lumen Designer Output is about 2300 lumens per lamp times 2 lamps equals total output of about 4600 lumens. Lumen has become the standard for defining light output of a lamp. Lumen Designer Output is light output produced after 40% of the lamp’s expected life has been used (or maybe it is 40% of the expected life remaining – I can’t remember). Anyway, half the lumens are directed upward in any florescent fixture. Therefore downward lumen output of one of these old florescent fixtures is about 4600/2 or 2300 lumens.

Research and Requirements. I researched shop lighting on the internet. I found an article that recommended about 100 lumens (light output) per square foot and several that recommended light in the daylight color temperature range – all related to woodworking shops. I bought into the color temperature recommendation, but had questions regarding the 100 lumen per square foot recommendation. I recently completed a kitchen remodel during which I installed LED recessed lights that provided about 40 lumens per square foot. The kitchen general lighting plan was developed by a lighting designer. The kitchen offers plenty of lighting. I reasoned that the kitchen and woodworking shop had similar lighting requirements. As it turns out and discussed below, 100 lumens per square foot for a workshop is a good standard.

A lamp with a color temperature somewhere in the 5000 to 6500 degree Kelvin is close to sun light in appearance. Color rendering which, if I understand it correctly, is an indication of how well the light interacts with an object to reveal its “true” appearance. The higher the value (CRI on a scale of 0 to 100) translates to better color rendering. For me, color rending was an important consideration because I apply finishes to sample boards in the workshop; however, not as important as light that lets these 60 year old eyes see better.

Material Selection. I decided to scrap the florescent fixtures and replace them with recessed LED lighting. I considered LED strip lamps, but these would present the same problem as the old florescent fixtures, namely they would be in the way of the duct work.

The recessed housings would be in the attic and the workshop is insulated. Therefore, I bought 6” air tight “new work” recessed housings rated for insulation contact. “New work” housings, instead of “old work” housings, were used because I had access to the attic. White trim kits for each recessed housing, were also purchased. The trim kits provide downward reflection for any stray light, offer a finished look, and were inexpensive. The housings and trim kits were bought at my local home center and totaled under $20 per housing.

I found LED spot lamps rated at 26 watts with a temperature of 5600-6800K producing 1900 lumens while offering a Beam Angle up to 120 degrees. The beam angle was important because I wanted light to spread throughout the workshop. A narrow beam angle would result in small puddles of very bright light. I found the LED spot lamps on Amazon and cost about $17 each.

I already had a 6.25” diameter hole saw designed for cutting 6” holes for recessed lights. It has carbide chips embedded in the cutting diameter. It was purchased at Home Depot.

Lighting Plan. I drew a scale drawing floor plan of the workshop showing machine placement and including the path of the duct work. The location of each LED spot light was placed on the drawing, represented by circles. Circles were drawn on the diagram at locations over or near critical work areas such as the workbench, table saw, etc. and located off of the path of the duct work.

The center of each circle represented the center of the recessed lamp. The circle perimeter represented 20% of the total light from one fixture that would illuminate surfaces that are 36” from the floor. The height 36” was chosen because most work occurs more or less at this height. I calculated that the diameter of the light pool from one LED lamp at 36” was 225 inches at a 120 degree beam angle. The diameter of the circles was 20% of 225” or 45”. Now, circles with diameters of 45” were arranged on the shop diagram, one circle for each recessed light. Each circle touched the perimeter of an adjacent circle. This arrangement ensured that areas not directly below a lamp would be illuminated by two or more lamps. So what does all this gobbly goop mean? In the end, the recessed lights are about 5’ from each other.

After drawing all these circles on the workshop plan, I counted the circles to determine the number of recessed fixtures needed, which was 12.

Since this lighting upgrade was expensive and occurring at a time when further expenses for dust collection were anticipated, I decided to only equip ½ the workshop with LED recessed lights. The old florescent fixtures were installed in the half the garage that is mostly blocked by the garage door in the open position. The old florescent fixtures are on a separate existing circuit from the recessed lights. Most of the machinery is located in the half of the garage where LED lamps were planned.

Installation. Satisfied with the lighting plan, work began. I turned off the breaker and removed all the old florescent fixtures. All florescent fixtures except for four that would be re-installed in the front of the shop at the garage door were scrapped. I recycled the florescent tubes, since these are said to contain mercury.

The position of each recessed light was marked on the ceiling. Since a tape measure flops all over the place, I cut strips of wood that were then clamped together with spring clamps to represent the distances from the referenced back and side walls as specified in the workshop plan. One end of the clamped strips was placed against the referenced wall to discover the correct distance from the wall at the opposite end of the clamped strips.

Then the attic was checked to ensure there were no obstructions that would prevent placement of the recessed housing. Adjustments in the light positions were made when needed, usually by only a couple of inches.

With the final positions marked, holes were cut for each recessed housing. Then electric cable was run to each recessed light. Then I entered the attic, contorting myself into positions I had not been in for years, and installed the housing and made the electrical connections. I picked up power for the circuit from the drop used to power the old lights. The circuit was tested before powering up, Trim Kits and LED lamps were installed, and I was done. Well except for the test of turning the lights on.

Results. Based on the back of the envelope calculations I made above, power consumption of 1500 watts (150 watts x 10 old fixtures that were replaced) was reduced to 312 watts (26 watts x 12 LED lamps). The recessed LED lights consume 20% of the power that the old florescent fixtures consumed.

There is a slight reduction in lumens flooding the shop. The old fixtures produced 23,000 usable lumens (2300 usable lumens x 10 old fixtures). The 12 recessed fixtures produce 22,800 lumens (1900 lumens x 12 recessed lamps). This is about 100 lumens per square foot and in line with shop lighting recommendation discovered during the planning.

The LED recessed lights perform extremely well. There is a less than ½ second delay from flipping the switch and light flooding the shop. The LED lamps do not seem to mind cooler temperatures. The workshop is a good bit brighter than it was prior to the installation. I believe that the brighter workshop is due to the higher color temperature of the light, not simply the lumens emitted. Others who have entered the workshop after the upgrade have all commented that the shop is bright.

The area around the garage door continues to be illuminated from the old florescent fixtures. At some point, I may replace these old fixtures with 4’ LED strip lights, which directs light downward only, are very efficient, long lasting, and offer a range of color temperatures. However, these are expensive at about $100 or more per fixture. If I upgrade in this area, it will be when prices come down a bit more.

Lastly, there are a few spots that are dim. These dim areas are mainly storage areas and there is adequate light in these areas. Based on the lighting plan, I thought these areas would offer insufficient light for detailed work; but then I do little to no work in these areas. However, I may add additional recessed fixtures in the future, but for now these dim areas are not a problem and I am enjoying a well illuminated workshop.

Recommendations. Based on the achieved LED illumination in my shop, I recommend 100 lumens per square foot for shop lighting at a minimum. I would also encourage lighting designs to consider the color temperature of the shop lamps. It seems that color temperature indeed makes a big difference.


21 replies so far

View David Taylor's profile

David Taylor

326 posts in 552 days


#1 posted 01-06-2016 03:20 AM

Back when I was in Quality, we had our inspection areas checked with a light meter, and upgraded our lighting to 100 lumens per sq ft., to meet with industry standards. As you have found out, this standard is a good thing :)

When I built my shop, I faced the same set of problems you outline. I solved them with Light of America LED Utility Shoplight 40 watt 4200 Lumen 48” fixtures. I used eight of them in a 20×20 foot shop, 2 rows of 4, spaced about eqi-distant. This gives a total of 33600 lumens in 400 sq. ft., for an average 84 lumens per sq. ft. Not ideal, but pretty good. The fixtures were around $40 each, so $320 total for a pretty bright shop. I have added task lighting at the work bench to enhance detailed operations.

All of this was just a long winded way of saying that I agree with your choices, think you done good, I do wish I had done that 16% better, but am happy with my choices, and will move on now :)

-- Learn Relentlessly

View JBrow's profile

JBrow

818 posts in 385 days


#2 posted 01-06-2016 04:11 AM

David Taylor,

Thanks for the “Light of America LED Utility Shoplight 40 watt 4200 Lumen 48” fixtures” tip. I will keep this fixture in mind should I upgrade the remaining florescent fixtures. These are quite affordable at $40 each, especially when compared to those I was looking into.

View OSU55's profile

OSU55

1058 posts in 1454 days


#3 posted 01-06-2016 05:34 AM

Agree with all your research and conclusions, except for the light color range. True 5600k-6500k would be very blue to my eyes. I ended up with the Costco LED shop lights that are ~4300-4500k, just slightly more blue than 4100k florescents (which are the best color for me). 4000k-4500k works best for my eyes. Shorter wavelength bluer light starts doing funny things to human vision, especially with objects in motion. I also find it difficult on most machines to get enough light at the right angle all of the time, so most of my machines have task lighting to address this, which reduces the lumens/ft^2 requirement. Absolutely agree the light color temperature range makes a huge difference.

View jerkylips's profile

jerkylips

273 posts in 2035 days


#4 posted 01-06-2016 09:52 PM



Agree with all your research and conclusions, except for the light color range. True 5600k-6500k would be very blue to my eyes. I ended up with the Costco LED shop lights that are ~4300-4500k, just slightly more blue than 4100k florescents (which are the best color for me). 4000k-4500k works best for my eyes. Shorter wavelength bluer light starts doing funny things to human vision, especially with objects in motion. I also find it difficult on most machines to get enough light at the right angle all of the time, so most of my machines have task lighting to address this, which reduces the lumens/ft^2 requirement. Absolutely agree the light color temperature range makes a huge difference.

- OSU55

I would agree, and this was the part I was going to comment on. 4300k is considered “pure white”. When you get up to 5000k, you really start to see the “blue”. Anything higher , to me at least, looks really harsh.

Not exactly apples to apples, but I recently got a good price on LED bulbs & replaced all of them in the house. Most are 3500k, which I like – it reminds me of bright daylight. If you’ve ever used the GE Reveal incandescent bulbs, similar to that. Anything lower kelvin, to me, is too “yellow”. In a shop I could see going for whiter/bluer, but I don’t think I’d do 5000k. JMO..

View JeffP's profile

JeffP

573 posts in 856 days


#5 posted 01-07-2016 01:35 AM

The “stated color temp” is important…but don’t forget that there is a large variance in how that color temp is achieved with different examples of LED lighting (and even more so with fluorescent) .

A light can have a “perfect” stated color temp, but if it is all at one or two frequencies, it will give really weird color casts to some paints and woods.

Mathais Wendel on youtube has done a video or two about how to characterize the color spectrum of a light without expensive equipment (he uses a CD as a prism to see what it looks like).

Since LED lighting is still in its infancy, it is very easy to think you are getting a good deal, when in reality, much of what is stated about the light you’re drooling over is false or doesn’t tell the whole story.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

View JBrow's profile

JBrow

818 posts in 385 days


#6 posted 01-07-2016 03:07 AM

I really appreciate all these comments and cannot disagree with anyone. The conclusion from the discussion for anyone planning an LED shop lighting upgrade is that it is best to look at the light produced by the various LED lamps before making the purchase. It is clear from this discussion that light perception and a lamp’s color temperature specifications vary. The way one can see a demonstration of various lamps is visit a lighting showroom. At a lighting showroom, one can see how “bright” various lamps are.

I purchased LED lamps based on specifications available on the internet, where I made my purchase. It appears that I was blessed in my selection, since I achieved the results I had hoped for. But I confess that I did hold my breath when I flipped the switch.

If one can either wade through all the parameters that enter into a lighting plan or have a lighting plan prepared by a lighting professional, I recommend this LED upgrade.

View DirtyMike's profile

DirtyMike

461 posts in 367 days


#7 posted 01-07-2016 03:20 AM

I can personally vouch for the effectiveness of the lights of america shop lights. I was not a fan of blueish or bright white or LED, but my new lights have changed that. The light they produce is very close to sunlight on an overcast day. They show every flaw and imperfection in wood, metal, art. The amount of light they throw is very impressive and they are very bright. I believe they produce the best light from an led I have seen. It is nice not having to wait until the sun comes up to see the true color and finish of my work and at 35 bucks per light they are a steal.

View TinWhiskers's profile

TinWhiskers

179 posts in 417 days


#8 posted 01-07-2016 12:17 PM

Did anyone mention LED tubes to replace fluorescent tubes? I replaced the tubes for fifteen 48’’ fixtures as soon as their price was feasible. This was a year or two back. I went with 3000K as the 4000K+ tubes cost $23. I got mine on sale at $10 per tube. I did rewire the fixtures as in removing the ballasts. Now the higher K tubes are inexpensive. Power usage for the LED tubes has been measured at 1/3 that of fluorescent. I am OK with the color. Maybe I just got used to it. Would love a true color light, but in over a year none of the tubes has failed. I love not having the darn hum of crappy florescent tubes and not having to deal with faulty lights.

View OSU55's profile

OSU55

1058 posts in 1454 days


#9 posted 01-07-2016 01:10 PM

JBrow, just trying to help others considering LED shop lighting. Don’t take my comments as a challenge or anything. I’m wondering if there is an issue with your lumens/ft^2 math. 22,800 / 450 = 50.7 lum/ft^2, 1/2 of your stated 100. You made me curious, so I calculated mine, came out to 27.5 lum/ft^2. This level provides plenty of light for me, even detail work (as mentioned, I use task lighting on the lathe, drill press, and band saw because of all the situations where a shadow is cast, TS is fine w/o).

My experience with recessed lighting is that most do not disperse well and require higher output. This is highly dependent on the can and lens design. You do discuss dispersion, stating the bulbs used are 120°, but you may not be getting an actual 120° emitted from the fixture. The utility shop light design, hanging in the open, provide much better dispersion and reflection from walls and other surfaces.

View builtinbkyn's profile

builtinbkyn

651 posts in 405 days


#10 posted 01-07-2016 02:56 PM

To help color correct the color temperature of LEDs, should you find it to be too washed out and lacking warmth, you could add a few incandescent bulbs around the shop. That would diminish the cost savings from operating LEDs, but not by much. Unfortunately incandescent lamps are going the way of the dodo due to legislation.

-- Bill, Yo!......in Brooklyn :)

View JBrow's profile

JBrow

818 posts in 385 days


#11 posted 01-07-2016 03:17 PM

OSU55,

Thanks for your comments. I take no offense and do not interrupt your comments as a challenge. In fact I welcome your comments! The purpose of this forum in my mind is to help each other.

My math and your math are both correct. Your math is correct when I only illuminate the shop with 12 LED Lamps, and not the additional old florescent fixtures install in the front half of the garage. The LED lamps are on a separate switch from the florescent fixtures that are around the garage door. Since most of my machines and my workbench are in the back half of the shop, I used the LED lamps only in the back half. When using only the LED lamps, the front of the garage is illuminated, but too dimly to do any accurate work. I only did the back half of the garage due to the expense of the LED lighting upgrade combined with the added expense of upgrading my dust collection. Therefore, you are correct in that when only the LED lamps are on, I have 50 lumens per square foot. And these lumens are not evenly distributed over the entire footprint of shop.

Since I only covered half the workshop with recessed lights, I divided the 450 square foot area of the workshop in half to make the lumen per square foot calculation (100 lumens per square foot).

Also, I agree with your assessment of light dispersion from recessed lights. When I developed the lighting plan, I was concerned about work area “dead spots”. That is why I used 20% of the diameter of a circle when laying out the recessed housings. I wanted to ensure plenty of overlap of illumination from adjacent lamps, hoping this would eliminate these “dead spots”. I have noticed shadowing cast by various machines on the floor, which is not much of a problem. There is no shadowing at working height.

I suspect that LED strip lights are superior shop lights for the reason you mention, better distribution of light. The disadvantage of the strip lights is that these are more difficult (but not impossible) to work around when installing my duct work. Avoiding a 6” circle is easier than a 48” (or even 24”) line. However, had I been aware of Light of America LED Utility Shoplight 40 watt 4200 Lumen 48” fixtures for $40 each, I may have gone that way. If I had gone with strip lamps, I would have used a rectangle rather than a circle and would probably have sized the rectangle used to develop the lighting plan at 20% of the area illuminated by the strip lamp; again seeking to eliminate the dead spots and ensure plenty of light.

From what I have read and based on my own experience, the need for more light to see detail increases as one ages. A younger woodworker therefore needs less light, lumens per square foot, than us old guys. Anyone developing a lighting plan who needs only 50 lumens per square foot would save good money. I suspect that no matter how bright the workshop may be, task lighting is a great idea.

Task lighting is especially important anywhere you want to hit your line, like at a saw, or where seeing imperfections is important. I have yet to install these, but task lighting on the Radial Arm Saw, Bandsaw, and Sanding Table are candidates in my shop. I sometimes break out the flash light and shine it on the Radial Arm saw to get that accurate cut (don’t laugh); a real pain. Therefore, task lighting is on my short list of upgrades. I will probably build my own task lighting using under cabinet LED puck lights if I can’t suitable task light fixtures from the woodworking supply houses.

View ste6168's profile

ste6168

250 posts in 636 days


#12 posted 01-07-2016 05:50 PM

Currently, mine works out to be about 50 lumens per square foot, and for most tasks, I feel it is plenty. However, there are times when I wish it were brighter. I may add a few more of the Lights of America lights in the future. I currently have only 2, and some other lighting, in my shop.

View bkseitz's profile

bkseitz

294 posts in 775 days


#13 posted 01-07-2016 05:59 PM

Just finished upgrading my shop to (4) bulb t-8 fixtures this year (Daylight). These are around 4100 K per bulb and provide a good deal of light for my barn turned workshop. Yesterday I spotted new LED bulbs at Home Depot. I was fairly excited about the prospect of swapping out—with not rewiring—to LEDs at little cost till I saw the lumen rating. The brightest amount these is around 3000. That’s a significant drop. So until manufacturers get the Lumen rating up on these fluorescent replacements I’ll be sticking to the t-8s

-- bkseitz, Washington "if everything is going well, you've obviously overlooked something"

View splatman's profile

splatman

562 posts in 864 days


#14 posted 01-08-2016 02:29 AM



I sometimes break out the flash light and shine it on the Radial Arm saw to get that accurate cut (don’t laugh); a real pain.
- JBrow

Why not attach a small LED (puck or other) light or 2 directly to the RAS? Put the solution where the problem is. Let there be light!

View clin's profile

clin

514 posts in 461 days


#15 posted 01-08-2016 03:23 AM



Just finished upgrading my shop to (4) bulb t-8 fixtures this year (Daylight). These are around 4100 K per bulb and provide a good deal of light for my barn turned workshop. Yesterday I spotted new LED bulbs at Home Depot. I was fairly excited about the prospect of swapping out—with not rewiring—to LEDs at little cost till I saw the lumen rating. The brightest amount these is around 3000. That s a significant drop. So until manufacturers get the Lumen rating up on these fluorescent replacements I ll be sticking to the t-8s

- bkseitz

Keep in mind that T8’s are very efficient. LEDs are not that much better. So efficiency improvement should not be the driving force behind a switch form T8’s to LEDs.

-- Clin

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