Walterjn I did something similar at work. Replaced all the tubes with LEDs. Had to rewire the fixtures and remove the ballasts. Barn is now extremely bright when you turn them on.
I did that in my workshop/basement where 20 4' fixtures stay on all day. My total home electric bill is 18% less after I switched to LED's. I have also changed out most other bulbs in the house. My 4' LEDs were designed to work in ballasted lights so no work required there. I did have to replace the ballast on a double 20" "U" shaped bulb kitchen light.
