The four highest-impact energy upgrades for a Las Vegas custom home are: open-cell spray foam insulation throughout the envelope (replacing batt), a reflective roof membrane installed beneath the finish tile to reject radiant heat, high-efficiency windows on every opening, and HVAC specified at the highest SEER rating available. Whole-home water filtration is a worthwhile add for desert water hardness. Ruby Estate was built with all four, plus the water filtration system.