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Which color of fluorescent bulbs is best?

diamond

Well Known Member
I went to the store today to buy some fluorescent light fixtures and realized I now need to choose between "cool white", "natural light", and "daylight" T8 bulbs. The daylight have just slightly less lumens per bulb and are quite a bit more expensive than the others. I've never had fluorescents in my shop, so wondering which color of bulbs are recommended for RV building and general comfort to the eyes.
 
There's a whole profession around the answer. I suggest cool white.

Daylight is usually very blue, and "natural" usually isn't as bright.

If you want to go off the deep end, the two things to watch for are lumens (amount of light) and CRI, or color rendering index. But the short answer is that cool white balances these two factors.
 
If I remember correctly, all 3 choices at my store had the same CRI at 75 and all had about the same lumens at 2800 (I think). I certainly don't want blue light though, so thanks for the advise.
 
T8 Bulbs

I have Sylvania T8's Daylight, 6500K.
Package says 48" 32W. 2700 Lumens. 75 CRI.
Very white, like them...Picture taken without flash if you're wondering.
Is there supposed to be that much scotchbrite wheel dust on a 7A? There's my hat...

2sbn96f.jpg
 
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First off, spend the extra money and get the 8 foot fixtures, Cold start.
This is money well spent.
Fluorescent lights have to heat up to put out good light. The non cold-start lights struggle in a cold shop.
 
Cool white. Like Alton said, get the 8' high output (these are cold weather ballast also), you won't be disappointed. F96T12CW/HO.

Marshall Alexander
 
T12 fixtures

There is some sound advice on in some of these posts. Some are recommending 8' fixtures over 4s. That decision depends more on the layout of the lighting plan. It sounds as if you are on the right track with the T8s. The T5 54W fixtures are a good option, but depend on mounting height. Unless you are 13+ feet at mounting height, T8's are the better choice. Dont buy any T12 fixtures of any type, as this is a dying form, and bulbs are going to get very expensive, and hard to find in just a few years.
As far as color, I personally have 5000K lamps in my shop, I just recently relamped from 3500K lamps. I like the 5000K much better. If like it exceptionally bright, and don't like the yellowing. buy a couple of each, and take them home. Put them side by side, and have a look. Then you are only out 2 lamps, rather than a whole shop worth.
The 5000K are whiter. The 4100K are a little softer. 3500K has a yellow tint, and 6500K is getting into the blue-whites and is pretty harsh light.

Advice worth exactly what you paid for it.

Ben
 
Above 13'

If your mounting height IS above 13' (probably about 20-22') in a cold shop, then what do you recommend?

George
 
4 footers

My hangar is 45'x40 with 15 foot ceilings. I replaced the 4 foot 2 bulb fixtures with 4 foot 4 bulb T8 fixtures. To me the lighting is now perfect.

I would avoid 8 foot fixtures, just simply because of the cost and the slightly increased duty of installation and servicing.

There was a NYE party at a neighbors hangar. It is a huge hangar and he had 24!!! 4 foot fixtures that have 6 bulbs each. Interestingly, these fixtures have two circuits. The middle 2 bulbs on one circuit then all 6 on another. He turned them all on and I'm sure with the hangar door open, the light would be visible from Space!!!! Serious overkill and he admitted that.

Go with evenly spaced 4 footers, 4 bulb units. As noted above, 6 work great in my 1800 foot hangar.

If your mounting height IS above 13' (probably about 20-22') in a cold shop, then what do you recommend?

George
 
Just as a data point, our lights in our design studio are 5000 Kelvin. We can accept 5500k but all others are not within the spec. This provides the best color accuracy when trying to see colors.

We do have a specific area where we have a 4-light fixture wired up so we can switch each light seperatly. We have a 3500k, 4100k, 5000k, and a 6500k light. This is used for color matching. We also have a black light to see flaws in the parts.

As for easy on the eyes, that depends more on the ballest frequency. Too slow and your eyes will see the flicker and become more tired. If you shake your head like you are saying no, you can see the flicker in the bad lights. LED's are really bad for this.
 
On some of these attributes that are being described (and BTW there are a number of archived threads on the subject):

CRI:
Color Rendering Index (CRI) trumps all in my personal opinion, and most people that muck about with color temperature are usually using it as a proxy for CRI. This subject requires popcorn, but loosely it's important if you are painting, convenient if not. See http://en.wikipedia.org/wiki/Color_rendering_index for gory details. At least no one has recommended "full spectrum" lamps, which would drain an entire bar in order to discuss.

Length:
In general, 4ft is used inside (offices, libraries), 8 ft is used in warehouses and factories. 8 ft fixtures can be really loud!

Ballast:
Electronic is best, magnetic ones are being phased out. What you want to compare is efficiency.

High Output:
Designated as "/HO " on the tubes, these are more light per lineal foot. Of course just like RVs there is a tradeoff. Usually it's noise and efficiency. Efficiency is sometimes better in HO than regular, but never as good if you go all the way up to VHO. (Hint: hang any fixture from chains in order to avoid turning the ceiling into a sounding board that amplifies the noise.)

Bulb Diameter:
The number is diameter in eights of an inch, so "T8" is 1" diameter. T8s are more efficient than T12s. As others said, T12 is being phase out.

So my bottom line "cut to the chase" recommendation is:
  • Use 4 ft T8 Cool White fixtures with electronic ballasts, hung from chains, in your garage if it's heated and less than 12 ft ceilings
  • Use 8 ft if heated and high ceilings (saves some $$)
  • Use HO if temps will be below 50F all the time, or below 20 when you first turn them on.
 
Hello Mark,

Using Cool White here, plenty of light and easy on the eyes.

Also, painting the ceiling black will make it disappear, gives you the sense that it is much higher than it actually is, good for small spaces.

hsj3pv.jpg



pk
 
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spiral compact fluorescent bulbs

Do any of you folks use these in your shop as the primary overhead light source? When I run the numbers compared to conventional T8 fluorescent fixtures and bulbs, I come up with about half the cost for the same amount of light by using 42W compact fluorescents vs the 48" 4 bulb T8 fixtures. Am I missing something here? In my scenario, it's 18 of the 42 watt spirals compared to 6 of the 4 bulb T8 fixtures.
 
CFLs

Without wanting to get into a rant here, before using CFLs check on the disposal requirements as well as the hazards associated with them. A broken CFL can ruin your day.
 
Do any of you folks use these in your shop as the primary overhead light source? When I run the numbers compared to conventional T8 fluorescent fixtures and bulbs, I come up with about half the cost for the same amount of light by using 42W compact fluorescents vs the 48" 4 bulb T8 fixtures. Am I missing something here? In my scenario, it's 18 of the 42 watt spirals compared to 6 of the 4 bulb T8 fixtures.

We have a local builder who installed bare bulbs similar to what you are describing. His bulbs are on about 4' centers on a white ceiling and the light level is amazing, possibly more than I would want on a daily basis, but ideal for painting.

Here are some non-flash photos in the shop, notice the even light quality:

http://home.hiwaay.net/~sbuc/tvrvbg/_borders/skala-2.jpg

http://home.hiwaay.net/~sbuc/tvrvbg/_borders/skala-7.jpg

http://home.hiwaay.net/~sbuc/tvrvbg/_borders/skala-5.jpg

By the way, the Subie was abandoned after huge $$$$'s and the plane flies with a Lyc.

I definitely want a white ceiling in a shop for as much reflectivity as possible. That is more important to me than aesthetics.
 
Ok, sorry, but as a lighting professional, I guess I shouldn't be shocked about the amount of misinformation in these threads.

I have supplied hundreds of fixtures and lamps for hangars. Most of the time I use T8 unless the ceiling is over 15' and we are usually replacing Metal Halide at that point anyway and we go to T5HO.
It does not matter if you are 4' or 8'. You will have 4' lamps. T12's are going the way of the dodo. You can not manufacture the fixtures anymore and soon, you wont be able to buy the lamps. Modern T8 ballasting systems are rated for start temps well below freezing and take only a few minutes to warm up to full light output.
I always use 85 series lamps (+-85 CRI). Most stores carry the 75 series so you might have to go to an Electrical Wholesaler to get the tri-phosphor lamps. Most will take cash or cc.
The lumen rating is a function of the lamp operating on specific ballasts. There are many options with T8 but most of the time we are supplying standard 2850 lumen on a normal power factor ballast. Most fixtures are now being supplied with electronic ballasts of normal power factor but there are still cheapo low power factor ballast out there. Look at all the details including input watts to determine what you are buying.
I prefer 3500K lamps, but frankly it is a user preference issue. Colors will render differently but CRI is the biggest factor to this.
I would be happy to do a computer layout for anyone interested. I design for 40-50 f.c. maintained and use very low reflectances. If you have a white ceiling, walls, and floors, let me know and I will bump up the reflectances a bit. This level of lighting is a little low for very fine work, but excellent for overall general illumination. That is what my shop is lit too and most of the others I have done. PM me if you are interested in my help.
My hangar/shop is 2400 sqft, 9'6" ch, lit with (32) 4' 2-lamp T8 fixtures, npf, with Osram 835 lamps ( 85 CRI, 3500K). My fixtures are Lithonia DMW wraps with a Sylvania Electronic Ballasts, 10% thd.
 
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