I have been doing a bit of research lately on solar power, grid-tied and backup systems. As we plan to build a house to Passive House standards, is there any way to get around building it exclusively with AC power systems? I would like to build it with at least the lights running on a straight DC system to prevent waste from the inverter and again at the light source. This would also allow for smaller wire to be ran to the actual light bringing forward some cost savings. Is the National Building Code moving towards allowing people to do this or is it still set for AC power only with plug in every twelve feet?