I wire lights in so many sheds , barns and shops every year i get sick thinking about it. I agree with eddie though, fo a 24x24 you cant beat 4 sets of 8 foot long tandem T8 florescent lights. They eat up about 140 watts wer fixture but put out an amazing amount of light per watt.
Cost per fixture is less than $60 incl bulbs. Lamp life is in the 8-10 year range under most conditions.
The LED lights might seem like a good idea due to energy use , lamp life etc.... but with the amount of energy used operating a florescent light...especially only a part time usage fixture, you'll never save enough $$$$ to ever pay for the LED fixture in the first place.
I reciently buckled down and replaced the old (17 YO) Mercury vapor wallpack light on my shop with an LED retrofit kit only because the old fixture was nearing its end of life (bulb brightness). I figured id try out the new 40 watt LED retrofit kit offered at my supply house. Its supposed to replace a 175 watt MH or HPS fixture. Cost was $130.00. Easy install, and works great. Now the bad news. I only use this light maybe 1 hour a day in winter when running snow removal equipment. Figure 10 hours a week (High end) x 16 weeks = 160 hours. Old light would have cost 160 hours x 175 watts = 28KW of power @ 0.06/KWH here in Idaho....total cost of operating this light for winter was $1.68/year
New light 40 x 160 = 6.4 KW/year X 0.06 = $0.38/year. thats a savings of $1.30 /year . so in 100 years the light will have paid for itself.
kinda not worth it id say. I only did this to see how these retrofit kits work and install as i have some large commercial businesses that are thinking of retrofitting their parking lots. In these cases it may be worth it. I havnt yet sat down to see how the numbers crunch out yet.
