2 x 6 construction on exterior walls is often the first choice in insulation upgrades. I suggest “flash and batt” insulation. This method involves a 3/4 – 1″ layer of closed cell spray foam in wall and sill cavities for optimum air sealing and insulation value. A 2 x 6 wall cavity provides added R-value and therefore added energy savings. Dow insulation on the exterior sheating adds a thermal break on the entire wall assembly along with added R-value. Zollinger Builders provides energy star homes with HERS ratings to add a qualified number to the energy efficiency of our homes. HERS ratings on our homes range from 50 to 75.