5

Based on typical recommendation, my garage workshop should have 50k lumens of illumination. It seems challenging to accomplish this with LEDs - I would either need a lot of regular LEDs, or a good amount of very expensive high-intensity ones.

However, it looks like HID bulbs in the 250-400W range are much cheaper and have much better lumen output, and some are dimmable. Specifically, these are usually metal halide, sodium vapor and similar designs. Usually these are advertised as for outdoor or large warehouse/shop use. However, could I not install them in my garage?

Would it be difficult to manage the heat produced by such lamps? Would I have to suspend the lamp with some clearance from the ceiling? Is the mogul socket more complicated to wire than a regular one?

Details of the estimate:

  • For a workshop, the recommended light is 80-100 foot candles
  • My workshop is about 500 sqft
  • Based on the formula, lumen = 500 sqft * 100 foot candles = 50k
Improve this question
20
  • 4
    Note that even HPS (the less yellow-y sodium vapor) has absolutely awful CRI, and MH has a lot of control restrictions (can't hot restrike, for instance), so you'll have to keep that in mind when making this decision
    – ThreePhaseEel
    Sep 19 at 4:11
  • 2
    HID needs specific fixtures - you can't just wire up a mogul socket to line power, it needs to also have a ballast. You really need to get out of the idea of light bulbs and in to the range of integrated fixtures for this. See my answer for more details.
    – KMJ
    Sep 19 at 5:20
  • 2
    Honestly, you'd be better off with some standard E26 style sockets and UFO LEDs. Those will put out plenty of lumens.
    – Huesmann
    Sep 19 at 11:48
  • 2
    That sounds like an immense amount of light. What area? What lumens/m^2? What calculations did you base that on AND have you experimented with LED lighting over a smaller area to see how they fare in practice? Having movable spot lighting for special tasks may be a valid option. This can be easily moved and positioned. And, probably, not needed for most tasks.
    – Russell McMahon
    Sep 19 at 13:35
  • 1
    What "typical recommendation" are you talking about? I mean, I love a brightly lit garage, it'll be nice, but this is not how most garages are lit and I've never seen it "recommended" anywhere. I'm just curious.
    – jay613
    Sep 19 at 14:22

4 Answers 4

Reset to default
13

Sure you can. 'Low Bay' HID lighting fixtures are available. Since they are often noisy, they can flicker, and they're more expensive to run than LEDs you might even be able to find them used on your local Craigslist or equivalent.

Don't discount LEDs so quickly though. There are low bay LED fixtures available at a similar cost that make 10k+ lumens per fixture with pretty good color rendering, instant on, better efficiency than HID, and even 0-10v dimming.

You probably also want more than a few light fixture so that there are fewer shadows. That creates a strong reason to consider LED strip light fixtures, commonly available at home stores. They can make over 1k lumens a foot, so a half dozen eight-foot fixtures will make the 50k lumens you're looking for. They are even cheaper than warehouse lighting. You give up dimming, but installing two circuits so you can turn on two with one switch and four with the other gets you nice 'three way' lighting levels for only a little bit more lighting.

Improve this answer
10
  • 7
    For my workspace, I installed about a dozen 4-foot led strip light fixtures. It was a few hours of mounting and wiring, and it's absolutely fantastic having bright lighting with almost no shadows, no noise, and good color. That got me to about 70 lumens/sqft which is a nice easy working brightness.
    – KMJ
    Sep 19 at 5:17
  • Well, you're saying not to discount them, but for example this 250W MH bulb provides 25k lum for only $18. Whereas with an LED like this I would need 2-3 which is $56-84. And this LED is unusually cheap, so I suspect that it will have some kind of problems leading to hidden costs.
    – gomennathan
    Sep 19 at 18:12
  • 3
    @gomennathan You fail to include a fixture (most north of $150, cheapest I saw was claimed $99 but oops! "not available") for the bulb in your price comparison. But sure, have fun, see what happens when you skip that.
    – Ecnerwal
    Sep 19 at 19:39
  • 1
    @Ecnerwal If the real cost of HIDs is in the fixture, I'd be interested in seeing that. But you have provided no evidence, just threw out some numbers that cannot be verified. I don't see why you are so angry at this, it's a reasonable thing to compare the costs of different options for lighting a room.
    – gomennathan
    Sep 19 at 19:52
  • 2
    @gomennathan the real cost in HIDs is in the ballast and fixture. usalight.com/22-High-Bay-Fixture-250-watt-Metal-Halide-Pulse-p/… for an example. They are actually getting kind of tough to find new because LEDs are the same cost at this point and cheaper to run. Again, you can't run an HID bulb without a ballast. Not going to happen.
    – KMJ
    Sep 20 at 0:12
5

You can also light your workshop with pitch torches. It'll have many downsides, but should go over well with the Dungeons & Dragons crowd (not so much your insurance company, though.)

Good LEDs beat the snot out of HIDs of any stripe. HIDs take 5-10 minutes to reach full brightness, and a few bright point fixtures means lots of nasty shadows .vs. more distributed lighting. LEDs might take 0.5 seconds to fire up, and mostly that's on poorly designed dimmers rather than the LED itself (as seen when I removed the LED-rated dimmers from a set of dimmable LEDs as even that short delay was driving me nuts.)

Any HID lamp has a "ballast and starter" between it and the powerline. The starter may have to throw kilovolts to strike the arc. The lamp socket needs to be rated for that duty. If you're looking at "bulb cost" without looking at "fixture to support the bulb cost" your economics are WAY off. If you want "really bright LEDs" as a single bulb, LED HID replacements are made - just be sure to get one that's line-powered, ballast bypassed, not expecting a ballast to be hooked up. You may have to shop somewhere other than a blue or orange box store to find those, however. And it gets you the same issues with "few bright point sources lead to shadows" as actual HID.

Improve this answer
13
  • A thousand times: True. Those point-spot lights make mostly shadows. Strip led light are now mature tech
    – Martin
    Sep 19 at 13:36
  • 1
    The startup time is a significant detraction, as are the shadows. If the guy doing the archery class in college didn't show up 10 minutes early to turn the lights on, it was a very dim glow indeed from overhead while we waited for the targets to appear out of the gloom as the lights finally lit. Hard to do woodwork under those conditions.
    – Ecnerwal
    Sep 19 at 18:21
  • 3
    20 years ago in the old house I had a single Edison socket in the middle of a garage like you are describing. I put the biggest halogen bulb possible in there to light the whole place. It was not good, the shadows are just black, you can't make out any detail on anything not directly in the light. You cast a shadow onto your work you have to work around. I upgraded to 4 led shop lights a decade later and it was 100x better. Having non-point light is so much better.
    – Ukko
    Sep 19 at 18:46
  • 1
    @gomennathan, You don't need panel lights, you just need lots of point sources. In fact, the further apart those point sources are, the better... if they're equidistant from your work area. (Otherwise, more distance means less light.) You'll still have shadows (in fact, you'll have more shadows), but they'll be much less dark. Panel lights just make softer shadows... which is also good, but not as good as shadows that aren't as "deep". (Plus, you can add diffusers to cheap lights to get the same effect. Strip light diffusers are dirt cheap, too.)
    – Matthew
    Sep 19 at 22:12
  • 3
    @gomennathan take a peek at this article woodmagazine.com/workshop/lighting-wiring/… and notice how many lights there are around the shop. This is what you want. If you need 50k lumens to light a 500 sqft space, you probably want at least 10 5k-lumen or so fixtures. Otherwise it'll be shadow city, and a very unpleasant place to do any work.
    – KMJ
    Sep 20 at 0:15
5

Your specification calls for 80 - 100 foot candles.

But if you place one blindingly bright lamp in the middle of the workshop, then the area immediately below the lamp will be way above the required brightness, and the corners of the workshop will be gloomy and full of shadows.

Just getting the average brightness correct isn't the solution. You need the correct brighness across the whole workshop.

That's why other posters are recommending several lamps, or diffuse lamps (such as the LED look-alikes for fluorescent tubes).

Improve this answer
1

for example this 250W MH bulb provides 25k lum for only $18

Hook 120V up to a mogul socket and Bob's your uncle, eh? I wouldn't do that.

I would use these fluorescent tubes here, Sylvania FO32V41. $2.38 a pop for 2450 lumens, which is more $ per lumen I'll grant you... but

  • SILENT
  • much, much, much better quality light at 90 CRI
  • run cool so not a fire hazard
  • 2 seconds to light instead of 10 minutes
  • Actual soft light, not "burn tracks across your eyeball" like HID lighting and most LEDs.
  • not a few point light sources that cast mostly shadows.
  • fixtures are actually affordable.

So how do we hook up those fluorescents?

Nail some tombstones to your rafters, hook up 120V, and Bob's your uncle, eh?

Of course not. You know perfectly well, real fluorescents need a ballast and a UL-listed fixture. Well it's the same for HID lights, to bring it full circle and actually answer your question.

Difference being, HID light fixtures and ballasts are still pretty expensive, because the're sought after by the "indoor horticulture" crowd. Nobody wants fluorescents LOL.

  • Fixture: they're free on Freecycle. They don't fit in standard trash bins, and people will let you have them for free if you let them show off their new LED lights in their shop. Be sure to compliment them. Say you'll take the fluorescents because you promised to, but you might just do what they did instead. They'll love the ego stroke.
  • T8 electronic ballasts: cheap on eBay.

The above is what I actually do in my own shop for real, so yeah, I walk my talk.

Improve this answer
1
  • This is an answer to "what type of light should I use in my workshop" whereas the question is "can I use a HID in my workshop". You appear to think the answer is no, but since you've only offered a snide remark rather than explaining why specifically this wouldn't work, I don't think this helps much.
    – gomennathan
    Sep 20 at 4:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.