With the new energy requirements, we now use insulation between our 2 x 12 header material. We use to use 3 (three) 2 x 12’s with osb in between each one to make up the required 5.5 inches in a 2 x 6 wall. Now we just use 2 (two) 2 x 12’s with 2 1/2 inches of insulation. And with advanced framing techniques we Simpson StrongTie HH6 to hold the headers instead of trimmer studs. The pictures show the headers being assembled and one installed with HH6 hangers.