This is the most efficient home I've built yet. This house has a 5-in concrete slab 2x6 exterior and interior walls 2x8 stick frame rafters braced full cavity blow foam insulation. It has gas and electric to all appliances it currently uses gas appliances. Every light bulb in the house is LED. It has both metal roof and metal walls on top of a completely wrap plywood house and tyveck house wrap. The windows are vinyl very energy efficient the floor is commercial hardwood look vinyl flooring planks Waterproof scratch proof .