I have one end of a metal building, totally heated and ac as well. There is 4" insulation with the plastic backing. I had peg board panels made to fit the 8' height to the girder (?) Not sure what that iron is called. I do not have enough plug in's. It's amazing all the items that need electricity. Our outside temps range from -17 winter to 110 summer so the insulation is needed. Ceiling has 6" insulation. I share the building with my husbands business.