Barn lighting

You will generally get more light output per watt with fixtures designed for the T-5 or T-8 bulbs. They can be 30 to 60% more efficient than the older T-12 bulbs. (more lumens per watt) (T-5 is 5/8 inch diameter, T-8 is is 1 inch diameter and T-12 is 1.25 inch diameter tubes.)

Some fluorescent lights are designed for cold locations and others will struggle to start and work.