Janello

Shop Lighting Question

Recommended Posts

What is typically more important with shop lighting-  Higher Color Temperature  or  Higher Color Rendering Index?

 

The LED lighting I'm looking at for the new shop seems to give one and take the other. For example; one is 5000k at 67CRI the other option is 4000k at 82CRI.

 

I'm leaning toward the whiter light with less color rendering.....Which would you choose?

Share this post


Link to post
Share on other sites

You should private message Vic - he is the lighting guru around these parts. He was very helpful when I was designing the lighting in my shop.

Share this post


Link to post
Share on other sites

I have recently managed some lighting upgrades where I work, hundreds of thousands of $$ worth. My personal feeling is that higher color temp is better for working areas, although the CRI is probably more important for things like photography.

I know for sure that moving from 3000k to 5000k lights makes a HUGE difference in visibility, without actually increasing luminant power.

Had a vendor demonstrate with a photo light meter. Standing under a high pressure sodium light, measured 80 lux, but the low temp (2700k?) light seemed dim. Moved about 40' to stand under a metal halide light (4000k?) and measured just 50 lux, but visibility was much better. Both fixtures draw 400 watts of energy, same distance from the ground.

The 5000k LEDs we're switching to provide even better visibility, and less that 30% the input energy.

Share this post


Link to post
Share on other sites

OK, Funny thing... I was just about to post a question about shop lighting and this was first on the list of topics (great minds).

 

I have been considering LED's HD has some that are T8 4 bulb 4ft equivalent  7,100 Lumens for $99 each (anyone have experience with these?).  However I know LED lifespans depend greatly on operating temperature and not having them properly heatsinked will cause dimmer results and premature failure and given the price I cannot imagine these are going to be optimally designed.  Not to mention, I live in Texas and my shop is only conditioned when I am in it so heat is a concern as most lab conditions are rated for 77 f. and my garage easily gets into the 120's with insulation.  I have been pricing some of CREE's XQ-B emitters and think I could build a high quality 2x2 ft light outputting about 4000 lumens with a floor coverage diameter of about 20 ft from an 8 ft ceiling for $150ish each.  Taking into account the resistance of running these at 56mA and the aluminum casing I would be mounting them to I should be able to utilize a passive (conductive) cooling system (no fans or extra heatsinks) .

 

OR

 

I can run 3 new 2 bulb 4ft T8 light fixtures for about $20 more then the cost of just one of these LED domahickies...

 

I was thinking initially that I could produce a quality fixture myself for about $50 to $75 but am finding this to be difficult once you figure out the cost of the emitters, the drivers, the AC/DC power converter, etc. 

 

wfnhighlander - considering the amount of money your company invested I imagine you/they saw considerable benefit to make that kind of investment.  Is it a scale thing?  Saving 30% off a $10,000 annual light bill X multiple buildings I sure has a reasonable ROI... for a garage troglodyte the savings off 4 lights seems inconsequential.  The quality of light is important, very important, so if the LED's provide better light then a Daylight balanced (5000k) florescent then maybe that is my answer but if not, perhaps I should just save my money for more trips to the lumberyard.  the ~$300 difference buys a fair amount BF of Walnut after all :)

 

Any help or guidance would be greatly appreciated.  Being a lifelong wannabe photog I understand the importance of light but am afraid I may be overestimating it in this particular instance.

Share this post


Link to post
Share on other sites

Pdjms1, I would agree that scale is a big factor. Our energy cost for lighting alone approaches $100k per month, and the LED lights drop that by 60%, on average.

Lighting quality is on par with the 5000k T8 flourescents. At the current price point, those are certainly your best bet. The only advantages of the LED luminaires over flourescent in a small shop are longevity, instant full brightness in any temperature, and dimmability. I doubt those make up anything close to the cost difference.

Share this post


Link to post
Share on other sites

Here is why I am going with LED vs. T-8.

 

Point one- I theoretically will never have to change a bulb.

Point two- I already shell out way more than the average home owner for electric per month. Having a hot tub, pool, tiki bar, tv in every room, inlaws in basement .....etc...My goal is to change all lighting to LED.

Point Three- It's slightly better lighting than T-8 on the eyes

Point Five- They make much more aesthetically pleasing fixtures in LED than a T-8 troffer

Point six- No chance of buzzing or ballast replacement.

 

 

That said, I have T-8 fixtures in my garage now and they are still great lights. I just wouldn't choose them over all the LED options available for my new shop.

Share this post


Link to post
Share on other sites

Don't do it!  A CRI of 67 is very, very poor.  You will have issues with trying to match 2 pieces of wood.  They'll look good under your shop lights & then completely mismatched when you get them under natural or halogen light.  As far as accuracy is concerned, color temperature is more a matter of preference.  You can get high CRI in anything from 3500K to 6500K, but 5000K is genarally about the closest to natural light.  4000K is still really good.

Share this post


Link to post
Share on other sites

Estesbubba - Shops lookin' good! Wish I had that much floor space but the wife insists on parking her car in our 3 car garage… Not to mention about 1500 sqft of marble and wood floors set aside for the next rental rehab.  I did just find that Cree has plug and play troffers for about $130 and it seems like a better option then purchasing all the parts separately and building my own (time and effort) for more money.  

 

I did reach out to a friend of mine who has been a Master Electrician working for Lockheed for the last 20 years and he said they have been testing LED Retro kits, LED Replacement kits, etc and they are finding that in their environments even server rooms that the MTBF (Mean time before failure) is about 2-4 years.  He encouraged me to stay away from them for my little shop… Here in Texas, with the help of a friends and family discount through a buddy who started an electricity company, we only pay .05 cents per KWh.  I did some quick math between a 32W T8 62w per fixture and the 40W LED fixture and it would only take me 391 months to recoup the difference in the cost. Assuming (15 hrs per week * 22W difference = 330W per week * 52 weeks = 17,160 W per year or 17.16 KWh * .05 c per KWh = $0.858 per year savings per fixture even with my 4 fixtures that is saving me $3.43 per year)

 

Given the quality feedback from you guys, as always, and my friends recommendation to go T8… I think my scale is just way to small and the cost of energy is so little that the ROI just isn't there in my situation.  This will also make my wife happy because the light "issue" just went from probably a month of tinkering to a Thursday night project :)  And now I might be able to afford a shed to clear up some more floor space or there is always more walnut!

 

I have to admit when I first started looking I forgot to convert W to KWh and this all looked way more attractive, about 1000x more attractive to be exact. lol.

 

Thanks again to the input from all of you!  In an internet full of trolls Wood Talk Forum has really provided a place for enlightened and those who seek to be enlightened a chance to communicate (lighting pun intended, but sentiment was legit) 

  • Like 2

Share this post


Link to post
Share on other sites

pdjms1 - I would recommend going with High Output T8 fixtures and they don't cost much more. They put out about 30% more light over SO. I looked at T5 fixtures but think they were recommended for ceilings 15' or higher. 

Share this post


Link to post
Share on other sites

Don't do it!  A CRI of 67 is very, very poor.  You will have issues with trying to match 2 pieces of wood.  They'll look good under your shop lights & then completely mismatched when you get them under natural or halogen light.  As far as accuracy is concerned, color temperature is more a matter of preference.  You can get high CRI in anything from 3500K to 6500K, but 5000K is genarally about the closest to natural light.  4000K is still really good.

 

 

I'm listening!  I can get 4000k at 86CRI but would need a few more lights. The Lumens drop from 7,600 to 6,700. 

 

I am guessing 86CRI is acceptable?

Share this post


Link to post
Share on other sites

Janello - I'm not an expert but some things I read while doing research. First thing was to shoot for 100+ lumens per sq/ft and I'm around 120. Second, the warmer the bulbs the more lumens you need. So 10,000 lumens at 5000K will be brighter to your eye than 10,000 lumens at 4000K.

 

Don't know if any of this is true but I found it on the Internet, so it must be! 

Share this post


Link to post
Share on other sites

I would say 86 is pretty good.  I'm using Philips TL950 T8 lamps which have a CRI of 98 & they are great, but they also have a lower lumen output than an 850 lamp which has a CRI of 82.  I just put up more fixtures to compensate for that.  They are so cheap that it wasn't an issue.

 

With LEDs, the lumens/watt tends to go down the lower the color temp is.

Share this post


Link to post
Share on other sites

Ok, so i have my new lighting installed and am running a total of 7 4ft 2bulb T8 fixtures with Philips 850 bulbs (CRI 82 Lumen output of 2850 (i think)) and it is wonderful! I have a three car garage but only have the equiv of 2 bays lit for working with one 2bulb fixture over my wife parking spot (arg). Having better light makes such a difference in visibility and enjoyment in the shop. Only problem is now that its spring (here in Texas) my wife has me outside working on planting the Maple trees we picked up end of last year and building a couple of retaining walls, oh and finishing off the fence now that the farm behind us has been sold and is going to be more cookie cutter homes :*(  So looks like I won't be back in the shop for another month or so

Share this post


Link to post
Share on other sites

LED was a band wagon. True designed LED tend to last much longer than retrofits. There are bad apples as many makers rushed to fill demand. The longer we go, the better consistency should arrive. I wish it were better than "should" given the cost.

Share this post


Link to post
Share on other sites

2 questions after reading through these posts. I am getting mixed feelings about my future shop lighting.  I priced the lighting out and it is roughly the same cost where I live for both setups.  The other question I have though is I am also getting mixed opinions on how many lights I need to actually put up?  The space I am about to use to turn into my work shop is 45x21x12.  Any help would be appreciated. Thanks!

Share this post


Link to post
Share on other sites

thanks for the link.  It sort of helped but if I put in 1056_large.jpg these 2GTB 4 32 A12 lights in.  It says for this size room I only need 6 and that doesn't seam right that's all.  I was trying to see what it would do with led lights but I couldn't get it to work.

Share this post


Link to post
Share on other sites

Illumination from LEDs in a similar fixture will be quite close to the flourescents, but at a lower energy cost. If you can buy led at close the same price, I recommend it, as long term energy and maintenance costs shoukd be much lower. I personally prefer lights with a color temperature greater than 4500K. Higher CRI ratings help, too.

Share this post


Link to post
Share on other sites

Click on the green plus sign on the bottom left. Go through the list of lighting until you find something close to what you plan to install, then tweak all the parameters to suit your design.

Note: Some lights on the list cannot be tweaked. Keep hunting until you find one that is close that you can modify. Clicking a new plus sign will open a second tab to start over if you grab one of those elusive fixtures that you can't tweak.

Shoot for something close to 100 foot candles for a shop setting.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.