First, the energy calculations required us to add a heat pump. We planned on having no mechanical system. Apparently its more efficient to have an appliance? Also the windows had to be reduced to meet energy code too. If we were able to add 250 square feet say, there would have been no problem with the amount of windows. You are actually penalized for having a smaller house that attempts to be off the grid. The energy code made it less likely that we would indeed conserve energy. If we had a bigger house with a big AC unit, we would have fit the norm just fine. ARRRGH.