My shop is a little more than double yours in size with ceilings ranging from 9' to 11'. I have 64,000 lumens of light produced by 16 batten fixtures of about 2"x1 1/2" x 5'long. To get the same light levels in your space you would be looking at about 8 fixtures. Basically you are looking for about 100 foot candles or Lux per square foot, which is about 1,000 lumens, to get even light throughout the shop. I bought mine from China and 3 or 4 guys in the local wood club have bought since on my recommendation. Most recent one should have his in a few days. They were about $17US (late in 2016) each but the shipping will be the same or more (FedEx) but should still be within your budget unless you get dinged with high import costs. I you want to go this route let me know and I'll dig out the link to the company and then you can get what suits you or the equivalent Amazon product. Mine are 6,000K which is a colour temperature closer to mid day sunlight where indoor light from an incandescent bulb is about 3,000K to 4,000K. A warm light more like early evening sunlight.
Pete
I started out on exactly the same page as you, aiming for around 1000 Lux illumination using LED battens, and have been pleasantly surprised by how much proper levels of illumination have improved my enjoyment and productivity; Though personally went for 4000k temperature because I find it easier on the eyes...
As an aside, because lumens are about perceptible light; a "warmer" colour temperature fixture will give slightly less lumens for a given wattage, because the human eye is more sensitive to blue light as found in "cool" lights.
Doing lighting design well is difficult, but I've just been through this as part of refitting my workshop and can probably offer some pointers later from what I've learned; although have to cook lunch right now so may be a few hours
There's a couple of things to consider with lighting design to get the most out of it, first is the level of illumination, which is usually stated in Lux (Lumens per Square Meter), BS EN 12464-1 (Light and lighting – Lighting of work places – Part 1) gives a lot of detail on what level's are appropriate for different tasks, which are tabulated below:
This suggests that depending what you're doing, a luminance level somewhere between 500 and 1500 Lux would be appropriate.
Knowing that you can use the area of your space (for a 15 by 20 ft space, that's about 4m × 6m = 24m²) to calculate the total illuminance in lumens needed to provide that for your space, so taking a middling value of 1000 Lux × 24m² = 24000 Lumens total.
That's the easy bit.
The harder bit it physically laying those out so that you can achieve a fairly constant average illuminance, with minimal shadows; in this respect using a larger number of lower output fittings ("Luminares") spread across the ceiling evenly is a much better plan than a small number of high-intensity fittings.
You also have to be aware of any ceiling obstructions which will cast shadows/block light, and the reflectivity of your walls when planning this, as that will have an impact on how well the light is averaged across the whole room.
Putting that into practice, when I was lighting my 3.5m × 7.2m workshop with 2.2m ceilings, I went for three independently controllable sets of lights running longways:
- Two along the left and right edges of the workshop ceiling (white for reflectivity)
- 4 × luminaires casting 2000 lumens each
- 1200mm long "light batten" type lights
- 400mm in from the wall - (white walls which reflect most of the light back into the room)
- On 1800mm centers, with 900mm between the end walls and the first/last fitting.
- One along the center of the workshop ceiling
- 4 × luminaires casting 4000 lumens each
- 300mm × 1200mm "panel" type
- Suspended to be at the same height level as the luminaires at the side of the room.
- On the same 1800mm center pattern.
In practice that means I get a variety of illumination options:
- 300 Lux with just one set of side lights on (useful for welding, to have some working light, but ensure there's no backlight going down into my shield from behind),
- 650 Lux with minimal shadows cast with both sets of side lights on.
- 650 Lux overall with some shadows, but a more intense 1000 Lux light patch in the center of the workshop with just the downlights
- 1300 Lux overall with No Shadows and an area of around 1700 Lux in the center of the room where my Surface Plate and inspection bench is going
I really like the flexibility of that setup, and am glad I spent the time thinking carefully about how to lay out the fittings to get an even distribution of light, and minimise the potential to cast shadows over my work.
@Domingos, I hope that's given you some things to think about so you can work out what's important to you in terms of lighting, and how the layout of your workshop will dictate what type, size, number and power of luminaires you fit...
Hopefully once you've done that then you should be able to achieve your optimal lighting setup quite happily.
