First let me say I am not an expert on lighting, electrical work or anything closely related to the same. I have done a ton of research on back yard garages and have read several books on the topic. Besides, “expert” is best defined by looking at the component elements of the word: an “ex” is a has been or someone who is washed up; a “spurt” is a dip under pressure.
Up front: I agree with Stuart. Get professional advice from a lighting store. There are too many variables to consider and when added to the size of your shop an initial error in purchasing can prove quite costly.
You said you planned to do a lot of the work yourself. Is this just mechanical work or is painting involved? If the latter, you have many more issues to deal with vis-à-vis your lighting:
BRIGHTNESS
Rated in lumens, it gives an indication of how bright the shop will be lit:
• 850 lumens: 60-watt incandescent bulb
• 2,780 lumens: 150-watt soft white fluorescent bulb
• 3,050 lumens: 40-watt cool white fluorescent bulb
COLOR of light (Color Rendering Index (CRI))
The issue here is how close the artificial light comes to natural sunlight. The CRI scale equates sunlight to 100. A poor CRI results in your red 'Vette looking brown or even yellow. Well designed fluorescent bulbs have a CRI of 80 which is considered good – not great but good. I believe the best standard fluorescent bulbs will rate a CRI of 85 – well below an incandescent bulb.
• CRI – 95: Incandescent bulb
• CRI – 75-85: normal fluorescent bulb
• CRI – 62: Cool white fluorescent bulb
So, fluorescent bulbs generally have better brightness but lower CRI. Already a compromise.
COLOR TEMPERATURE
Quote from
Ultimate Garage Handbook, Richards Newton, page 75: “Scientists define color of light by its “color temperature”. The color of sunlight is determined by how hot the surface of the sun is, and the fact that our eyes are designed to be most sensitive to the light from our sun. Scientists have chosen to measure color temperature with units of Kelvin rather than Celsius or Fahrenheit, so the term appears a little strange at first (ED: as if talking about the surface temperature of the sun in regard to garage lighting ISN’T strange?!!?).
“A lower color temperature means a light appears “warmer”. The common household light bulb has a color temperature of about 2,800 Kelvin. A cool white fluorescent bulb has a color temperature of 4,100 Kelvin.
“Simply put, light bulbs with lower Kelvin temperatures (2,000 – 3,000 Kelvin) exhibit more light in the red/orange/yellow range. The higher Kelvin temperatures (greater then 5,000 Kelvin) will exhibit more blue light. Fluorescent (2,700 Kelvin), quartz halogen (2,800 Kelvin) and metal halide (4,000 Kelvin) lamps produce an impression of white light. At the equator at noon, you have 5,000 Kelvin.
• 6,000: very bright sunlight
• 5,000 – 5,500: Average daylight
• 5,000: full spectrum Fluorescent Bulbs
• 2,700 – 3,000: Ordinary Fluorescent Bulbs
• 2,800 – 3,500: Ordinary Light bulb
• 1,000 – 1,800: Candle Light”
You can spend some bucks and avoid the compromise between Fluorescent and Incandescent lights. "Some very expensive fluorescent bulbs are available from GE or Philips called Chroma 75. These are rated at 7,500 Kelvin with a CRI of 95. Chroma 50 is rated at 5,000 Kelvin and a CRI of ~90.” Compromise solved but at a cost
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As to the number of fixtures and type, this from
How to Design and Build Your Auto Workshop, David H. Jacobs, Jr, page 67: “Design your shop’s ceiling light capacity so that it will offer a minimum of ¾ watt of fluorescent light per square foot of shop space.” Your shop is ~1500 square feet. That would call for 1125 watts (1500 x .75). This translates to 19 x 60-watt bulbs (actually 18.75 but try and buy .75 of a bulb these days) or 14 x 80-watt bulbs (1125/80 = 14.06). Your call on whether you use 4-foot tubes or 8-foot tubes; ceiling space and obstructions would play in this consideration. Personally, I think too much light is just about enough -- but then I am 50+ years old and been working on computers since 1984
Then there is recessed lighting ($$$), spot or focused lighting for close work on benches, in-floor lighting under a lift, lights in the wall at eye level (again, lift work), etc.
Like I said: talk to a pro, like Stuart said.
Craig
) - one small flicker and you could be in the dark for a little bit.