Decision Time - T8 vs. CFL's & Cans

I could use some expert opinions and assistance.

I am working on a decision between T8 tubes and recessed cans with high-wattage CFL bulbs. Now, before you jump to the usual conclusion about can lights, let me explain. Please read before responding.

-I am lighting a 24’ x 40’ shop, with 12’ ceiling, it will all be sheet-rocked and painted white from bench-height to ceiling. It is not even in framing stage yet, so anything is possible, and no access issues exist.

I have attached two diagrams, the first one show the placement of thirteen 8’, 4-bulb T8 fluorescent fixtures, for a total wattage of 4bulbs x 13fixtures x 32watts=1664 watts, or 1.7 watts per sq/ft. Lumens per sq/ft=148. At Lowe’s these fixtures are $40 each, and the bulbs about $3 each, for a total of about $700. This setup consumes at least 1664 watts of power to operate.

The second diagram shows the placement of 14 recessed IC-rated can lights, each with a 250-watt-equivalent CFL bulb, for 14bulbs x 250watts=3500 watts or 3.6 watts per sq/ft. Lumens per sq/ft=52. The cans are about $7 each (less by the 6-pack), and the bulbs are $16 each, for a total of about $320. This setup consumes about 770 watts to operate.

The specs for these CFL bulbs are here:
Manufacturer: Energy Miser
Manufacturer's Part #: FE-US-55W-50K
Screw-In Compact Fluorescent
Wattage: 55 Watt
Incandescent Equivalent: 250 Watt
Initial Lumens: 3,600
Life Hours (Avg.): 8,000
Color Rendering Index (CRI): 80
Full Spectrum 5000K
Dimensions: L 8.39 in. x W 4.45 in.
Link to bulb site:
http://www.1000bulbs.com/55-Watt-Compact-Fluorescents/8742/

The reason I am thinking recessed fixtures, is because if I mount them in standard porcelain screw-in bases on the ceiling, the combination of base and bulb would be hanging about 9.5” below the ceiling. Seems like that is asking for them to get hit with something, even with a 12’ ceiling.

With recessed fixtures, I can slide the screw-base plate up and down inside the can, and get it to where only the “twisty” part of these big CFL’s is below the ceiling, so only exposed to about 4-5” below sheetrock, which is similar to a fluorescent tube fixture height. This should allow the light to disperse horizontally, and to reflect off of the ceiling as well.

These are IC rated recessed cans, so they are not a “hole in the envelope” because I will have blown-in insulation over the top of them.

In Veno’s thread here:
http://www.garagejournal.com/forum/showthread.php?t=38658
He used 16 large CFL bulbs (he used the 420-watt-equivalent units), in standard Edison bases (porcelain screw-in bases) to light a 40’ x 50’ shop, with a 17’6” ridge and about 14’ side walls. That’s 2000 sq/ft, or 3.36 watts per sq/ft.

If you look at the after pics in his thread, it sure looks like he has plenty of light in there.

I’d expect that with the CFL’s, I am proposing, in the position I am proposing, and with a 12’ ceiling height, I will have even better bench-height light than Veno ended up with. Additionally, unlike fluorescent fixtures which go in after the sheetrock, I can light these up while still in open framing, to validate the coverage, and can add cans if needed in specific areas. I am a little concerned though about the major difference in Lumens/Sq-Ft. I can't find any good information on how to calculate or estimate light levels, and whether to use light watts, lumens, foot candles, lux, or what?

In addition, the CFL arrangement should save me 50% of the electric bill that the T8 tubes would consume.

Ok, let me have it. Give me your feedback, good or bad, and why you do or don’t think this is a sound idea.

I used 24 6" cans in my 20x25 garage divided into 3 zones....I do wood working so recessed was the best choice.

I'm using 120W (23 actual watts) bulbs. On the right side are warm white, left side Day Light......(around 5000k I believe). The warm whites were such a great deal at Costco that I couldn't pass it up...4 bulbs for less than $4.

I prefer the Day light....but what I have now is fine....I don't need any additional light....

If I were to do it again? I wouldn't change a thing.

John,
It looks like you have reflector bulbs in there (on the right anyway), rather than "curly" bulbs. What type are they?
Do you have specs for what you used?
It also appears to me that you have them about 3~4' apart?

I'd recommend the T8s. I put CFL flood lamps in my garage on my 10ft ceiling. They didn't give me the light I wanted. I changed over to T8s. Yes, I'm doubling power consumption, but I more than doubled the available light. Long tubes seem to light much more evenly than the CFLs.

Gary S said:

I'd recommend the T8s. I put CFL flood lamps in my garage on my 10ft ceiling. They didn't give me the light I wanted. I changed over to T8s. Yes, I'm doubling power consumption, but I more than doubled the available light. Long tubes seem to light much more evenly than the CFLs.

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Gary,
Would you mind sharing a little more info?
What are the dimensions of the space you are lighting, and how many CFL's of what type were you using before switching to T8 fixtures, and how many T8's did you switch to?

I'm only lighting one end of my garage. It is 24x24 and I put up only 4 sockets in the ceiling. The four 26 watt CFL floods weren't enough light for that large an area. I switched to 4 4ft dual lamp T8s for 64 watts per socket. The consumption more than doubled, but I have great light with the 4 foot tubes. My ceiling is silver reflective foil, and the walls are painted white, so I have good reflectivity for the lights.

Steevo,

I'm considering the same setup, but I was planning on using the same CFL setup as Veno. Looking at your design, how did you calculate the floor coverage of the canned CFL? (the bigger circles) I gave mine a wag of 30 degrees and that only covers around 6 ft in diameter on the floor from 12 foot mounted height

jdub

Steevo said:

I have attached two diagrams, the first one show the placement of thirteen 8’, 4-bulb T8 fluorescent fixtures, for a total wattage of 4bulbs x 13fixtures x 32watts=1664 watts, or 1.7 watts per sq/ft. Lumens per sq/ft=148.

The second diagram shows the placement of 14 recessed IC-rated can lights, each with a 250-watt-equivalent CFL bulb, for 14bulbs x 250watts=3500 watts or 3.6 watts per sq/ft. Lumens per sq/ft=52.

Click to expand...

For the CFL's you can't go using the 250-watt equivalent because you're comparing fluorescent bulbs (tube) to fluorescent bulbs (CFL). It should be 55x14 = 770 watts, so like 0.7 watts per sq/ft.

That's why your CFL lumens are a third of your T8 lumens - it's going to be a third of the light. Plus those T8's are going to throw the light a lot more uniformly than those recessed lights. Much more usable light IMO in a garage.

jdub,
I looked at veno's layout with 14~17ft. ceiling, and determined it to be 125 sq/ft per bulb. I decided that even though my ceiling will be between 2' and 5' lower than his, I would assume half the sq/ft per light and came out with about 68 sq ft per lamp in my design, at 250-watt-equivalent bulbs, as compared to his 400 watt units. I am also assuming a wider spread than 30 degrees, since I intend to have the "bulb" portion of the CFL below the ceiling line, sticking out of the can. This will get me the most bang for the bulb by allowing wide dispersal and reflectance as well.
The reason I thought about using recessed cans instead of just screw-bases is to reduce the below-ceiling profile to only the part of the bulb that provides light.
I have attached a crude diagram of what I am envisioning.

scotto,
You are right, using watts to compare lighting is a waste of time since it really refers to power consumed and not light output. We should use lumens or some more scientific measurement. The T8 design works out to an average of 148 lumens per sq ft, and the CFL design to 52 lumens per sq ft. so there is a clear advantage there for T8's.
But nowhere that I can find online gives any recommendations as to what is a good lumen level for work. They all use footcandles, which gets way too confusing, and I can't find a usable lighting calculator that will let me input light types and locations and calculate footcandles at bench height for me.
So, I was using a "good-ole-boy" method, by looking at what veno ended up with and guessing that higher-density at moderately lower lumens, and a lower light height would result in equal or better lighting.
Not too scientific, but it makes my brain hurt less

I did find one obscure reference to footcandles required for "precision" work, and it recommended from 75-150.
Another article stated that general footcandles to lumens calculation was to multiply square footage times footcandles desired, times 2, to get lumens needed.
So, for a 24' x 40' shop, with 100 footcandles of lighting:

24x40x100x2=192000 lumens of total lighting.

Divide that by 13 (number of T8 fixtures), and I need 14,000 lumens per T8 fixture. The F32T8 bulbs I looked up were rated between 2700 and 3100 lumens, so a fixture with four bulbs would be right about 11,000 lumens of output. Just a bit shy of recommended footcandle levels.
Using the CFL scenario, and the 3600 lumen rating of the bulbs listed above, this methodology says I would need 39 of the CFL bulbs to equal the output of the T8 fixtures, and 53 of them to get to 100 footcandles of light.
At that point, the capital purchase cost and the operating costs are nearly equal and the extra work of installing, wiring and cutting in 39 can lights is a lot harder than six or seven ceiling boxes for T8 fixtures.

Hi guys.. I seen my name come up so I thought I would comment..

In my shop.... I am overtly satisfied with my solution... I have very little shadow casting.... and its bright when all 16 are fired up... I have them lit in groups of 4....


so for whether is bright enough.... I invite any one in the area to drop by and have a look see... the Lights I chose were 6500k daylight....

I am by far no lighting expert.. but after dealing with t12 4' fixtures for many years.. the CFL is a god send of simplicity....

In my own 24 x 26 attached garage I had four 4' Shop light t12's.... they sucked.. but sucked less than the 3 100watt incandescents .... I have since replaced the 4' shop lights with 4 55watt 5000k CFL's and have 4 times the light I did with any other solution. I ventured in to the T8 realm for 2 years and was disappointed by longevity and total cost of ownership....

May haps it's the heat here... (south east texas) but in non enviromentaly controlled conditions.. I have had very poor luck with "T" fixtures.... My good friend has a shop with 4 8' twin bulb T8ho's the ballast lasted two years... he saw my solution.... and he now is converting...


IMO the CFL is low cost of ownership... less obtrusive, easy to replace, easy to store, you can take them with you in 10 minuets, when they go bad you get new ballast and bulb when you replace them..

they do humm a bit...

but over all.. I am so happy with this solution I could just pop...

Like I said.. if your in the area and are a doubting Thomas.. PM and Drop in for a Dr.Pepper! and a light show

+ 1......I wouldn't do mine any different either.....

One extra point to add to Veno's list.....with tubes, you don't have any choices in wattage....with t8 it's 32w....t12, 40w....all have the same aprox light output...

With CFL's, you have a full range of wattage bulbs and color....you can mix and match as necessarey....

Steveo....some of the bulbs are PAR....basically, a standard CFL with the PAR reflector on it....those were the bulbs that were real cheap at costco....like less than $1 each....on some of them you can actually pull the reflector off if you try hard enough....I still need to work out which trim bezel I'm going to use on the recessed can...I will most likely save the PAR bulbs for outside use and use exposed bulbs inside...that way they stay up inside the can....it's only a matter of time before I whack one with a 2x4....

The brightest bulb I have right now is 23w, or 120 equiv. And like Veno, I don't have shoadow problems....

I almost went with 32 cans total....but after doing some tests, settled on the 24 cans....once all the cabinets are in I'll add task lighting which will give me the direct light I need for the close in work.....

ddawg16 said:

I almost went with 32 cans total....but after doing some tests, settled on the 24 cans.........

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24 cans to cover what size space, ddawg?

I have a 25 X 75 shed that I partitioned off, into a 25 X 45 shop. Although I do not have any pictures, and the walls and ceiling are yet to be finished, I used porcelain screw in bases, with 250W equivalent CFL's. I have 22 of them in that space, and am very happy with the results. Alot less than buying T8 type fixtures. My ceilings are also 12 foot, and dont have any problems with hitting them. I an not concerned with having them recessed in the ceiling. In my opinion, it's a very cost effecvtive way of getting alot of light. Good luck with your decision.

I went with T8's, if for no other reason than I hate cfl's. I have tried about 12 different kinds in the house, and thrown every one of them away less then 2 weeks into the use. I just can't stand them.

I have 9 2 bulb 4' t8 fixtures in my 19x23, and it's about right. I certainly wouldn't go less.

nissan_crawler said:

I have 9 2 bulb 4' t8 fixtures in my 19x23, and it's about right. I certainly wouldn't go less.

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That sounds about right. I have 4 of those fixtures in my 10x20. Could probably use 1 more.

Steevo said:

24 cans to cover what size space, ddawg?

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20'x25' on the bottom level....3 zones
1-Front of garage....basically around the perimiter of the garage door when up.
2-Right side of rear of the garage....where my workbench and bar will be.
3-Left side of rear of the garage....where most of my wood working tools are.

Upstairs I have 4 4' t12 fixtures....stuffed inside plastic cases....which have already earned their keep for the number of times they have been hit.....translation...no broken tubes......

Steevo said:

I could use some expert opinions and assistance.

The specs for these CFL bulbs are here:
Screw-In Compact Fluorescent

Click to expand...

Edison-base (screw-in) CFL's are targeted at the retrofit market. The advantage is that they're made by the zillions and are inexpensive.

There are several disadvantages for using them in new work:

1) They're built to a price point. A very low price point. Out of 50 or so in my house (all Ikea 11W units), about 25% have been replaced in a little less than 3 years. Power-on hours doesn't seem to be a particularly important factor in which ones fail. By contrast, my garage lighting (which gets used pretty heavily) is 4-foot T12HO's and 8 lamps have been running without a single failure for 15 years.

2) With a screw-in CFL, you're paying for lowest-cost electronics in the base of the lamp. By changing to a fixture with electronics and a standard miniature fluorescent lamp, you'll have better electronics and lamp replacement should be less expensive. On the other hand, initial cost will be higher and you can't easily change to different wattage lamps if you need more or less light.

3) Apparently some jurisdictions will no longer pass Edison-base fixtures in new work - they think that you might put incandescent lamps in them at some point in the future. There was a thread on this board some time ago where someone bought that type of fixture "at a great price" from the local home center, and got flunked on inspection.

(all Ikea 11W units)

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I would consider that to be the main reason of failure.....

I have a CFL in a end table lamp that has been in service for about 6 years now....the CFL in the hallway has outlived 3 incandescent lights...and still going....

I have pin type CFL's in the kitchen over the sink....I replace the bulbs about every 3-4 years.....bulbs are PIA to find....and you don't have any color selections at the box stores....

The CFL's we use for night lights have been in service for about 5 years....still going....

I have 2 4' T12 fixtures in the attic of the house....gets used maybe once a month....gone through 3 bulbs already.....as soon as I get time to find a good edison type fixture...the T12's are coming out and CFL's are going in...

As CFL technology improves, I can upgrade without major changes in fixtures....

If LED technology improves (and price comes down), I can switch to LED's without changing fixtures....

I think CFL's are a good way to go....for now...

Terry Kennedy said:

Edison-base (screw-in) CFL's are targeted at the retrofit market.

There are several disadvantages for using them in new work:

1) They're built to a price point. A very low price point. Out of 50 or so in my house (all Ikea 11W units), about 25% have been replaced in a little less than 3 years.

2) With a screw-in CFL, you're paying for lowest-cost electronics in the base of the lamp.

Click to expand...

My CFL's were not cheap... the 55watt=250 incandescent. have been in service in my attached garage for 4 years..@ a cost of 16.00 each

the ones in my new shop. 105 watt=400+ watt incandescent. cost 22.00 each... times 16 bulbs+ reflectors at a cost of 13.00 each plus shipping.. the total per fixture came to just under 40.00 per.. compare that to the 6 or 8 bulb T8ho high bay, low bay fixtures and bulb cost time 16 fixtures and 6500 kelvin bulbs...

the total cost for my shop was around 640.00 if i went with high bays.. the cost would have been closer to 3,200.00

thats a lot of CFL's

I used both cans and t8's. Cans on 2 seperate switches. and t8's on 2 more.
I fugured if i was going into the garage for a short period of time i could use just the cans. then if i needed more light, i could use them all.