How many fluorescents for a 24x26 garage?

[Steve Strickler]

Mike,

Hear, hear....

I was just scrolling down to see if anyone mentioned bulb temperature. I SWEAR by my T8 Phillips Alto Natural Sunshine bulbs!

Not to be knit-picky, but actually 6500K is kinda a cool sunlight (artic). Somewhere around 5000K is full-spectrum sunshine/sunlight. They rate their bulbs on a 100-scale on their abilty to show colors accurately. The 6500's rate a 79 while the 5000's rate a 92!

The bulbs are not cheap, but are worth every penny, in my opinion. It is VERY stimulating to go into my shop on a dreary winter day and get full-spectrum sunlight!

[Rob Beckers]

I'm running F32T8 Excella full spectrum / daylight fluorescents. They are 5700 Kelvin, 91 CRI, and cost just over 3 bucks when bought per case of 30 (see http://www.1000bulbs.com/product.php?product=4026). Most of those went into my shop, I have a few left that I intend to use for an excersize room. The light is very 'white', personally I like it, colors are rendered very close to what they look like in natural light (the main reason I put them in). Next to my shop is the heating/pump/water room with the same fixtures, but regular white fluorescents in them. The difference is striking, the Excellas are much whiter and also quite a bit brighter per bulb (though I suspect part of that is a trick of the brain, related to color).

All F32T8 fixtures have electronic ballasts if I remember right, you can't get them with magnetic ballast. In my case they come from a local DIY store (a Canadian chain named 'Rona'), two bulbs per fixture, with a cover/diffuser so the bulbs don't get dusty. There's no sound from the fixtures at all, completely silent, and they are instant start. The only downside is price, I believe I paid around $30 each for them.

-Rob-

[brett widenhouse]

I just wired and hung lights for my shop/tractor storage barn.
24x40. I used 8' lights, 2 rows of 3 lights each, then added an extra one over the bench area and an extra one over the tablesaw area. Seems pretty bright in there to me. Total of 1600 watt, on two switches.

[Jeff Fritzson]

Steve,

When I did the lighting for my shop I used this calculator http://www.gelighting.com/na/busines...kit/layout.htm and I am thrilled with the results. It is very much like daylight in my shop with minimal shadows. For my 20 x 21 garage I have 6 - 8' fixtures that each hold 4 - 4' lights. I got a great deal on some T8 lights with a CRI of 82 (5000k)

Regards,
Jeff

[Mike Jory]

The exact color temperature of a light is not directly porportional to the CRI. That is why the 6500K is a target. Sunlight is closer to 6500K than 5000K.

The Color Rendering Index, or CRI , of a source indicates how well it renders eight standard colors compared to a perfect reference lamp of the same color temperature.
The comparison is only valid for lamps of the same color temperature. The CRI Index ranges from 1 to 100. A lamp with a CRI of 80 will render colors better than a lamp with a CRI of 50.

Although a CRI is a good measure when comparing two lights of the same color temperature, it does not necessarily make sense when comparing lights of different color temperatures. A very yellow incandescent (low color temperature) will have a CRI of 100 (by definition), even though a much better looking flourescent (6500K) may only have a CRI of 85.

Source: http://ise.stanford.edu/class/psych2...eng/7color.htm

[Dale Sandford]

Since energy costs will most likely continue to rise, you may want to look at the the efficiency of your lighting. Here are a few generalizations about flourescent light efficiency. These are generalizations and of course there are exceptions, so if you really care you need to look at things case by case.

1) T8 (1") bulbs are more efficient than T12 (1.5") bulbs.

2) Electronic ballasts are more efficient than magnetic ballasts.

3) Normal output (NO) bulbs are more energy efficient than high output (HO) or very high output (VHO) bulbs. The high output bulbs put out more light, but consume more watts per lumen (unit of light).

4) Very high CRI (>90) bulbs often put out less light (lumens) than an equivalent lower CRI bulbs. A compromise is to use cheaper more efficient bulbs for general lighting and use the expensive high CRI bulbs for finishing areas where the color really matters.

5) New bulbs put out more light than bulbs that have been used.

6) Fixture reflectors and fixture position greatly affect the amount of lighting needed.


If you want to calculate energy efficiency, lumens per Watt is usually a good measure. Take the number of lumens and divide by the nomimal bulb wattage. (Actual power consumption varies depending ballasts, line voltage, temperature, etc.) The higher the lumens per watt, the more efficient the bulb. Note that most manufacturers provide both initial lumens and average lumens. The average lumens take bulb aging into account.

-- Dale

[Chris Padilla]

Dale,

Nice summary. I'd like to add: PAINT EVERYTHING IN SITE WHITE!! There is no better reflector in your shop/garage than the ceilings and walls and if they are white, they will only enhance your chosen light fixture and bulb of choice.

However, there is no more BORING color than white and to paint everything white but I think it really helps spread the light out nice and evenly throughout my garage.

[Matt Meiser]

Nice summary. I'd like to add: PAINT EVERYTHING IN SITE WHITE!! There is no better reflector in your shop/garage than the ceilings and walls and if they are white, they will only enhance your chosen light fixture and bulb of choice.

Amen to that! When I was painting my shop, it was like someone was turning on lights as I went. And eventually you'll end up with a lot of stuff hung on the walls to make it less boring.

[Brad Noble]

I have a 16' by 24' shop in my back yard. I recently aquired 10 three bulb T-8 fixtures. 4' long with electronic ballast. Only problem, they were take outs and have a 277 Volt ballast in them but guess what, they work fine on 230 Volt. I have three way switches set up with a total of two circuits for these lights. Two fixtures are on one circuit for those times when I just need to run out there for a tool or whatever and the other eight on another circuit for the main shop. I have 120 Volts feeding the switches which in turn only power on/off a couple of relay switches which carry the 230 Volts to the fixtures themselves. So far, works great! You can never have too much light. I have one bulb for every 12.8 sq. ft. I also have 8 1/2 ft tall ceiling height.

Brad

[Doug Littlejohn]

I'm running 9, 8 footers. About half have the good daylight bulbs. This is more than enough background light to work with (really rather bright), anywhere where I need more light I will drop in a 4 foot unit or some sort of auxillary lighting.

Also, I did mine on two circuits so that if the breaker were to trip at night, I won't be completely in the dark.

You've got plenty of advice on what bulbs, etc., so I'll just reiterate one more thing. I went with the 8 footers because they are commercial units which should have significantly greater reliability.

Sherwood