Utah’s Wasatch Front averages 222+ sunny days per year at 4,200 feet elevation with exceptional solar irradiance. Passive solar design capitalizes on this through: south-facing glazing (within 15–20 degrees of true south) for winter solar gain; overhangs sized for 40.5°N latitude (admitting low winter sun, blocking high summer sun); east-west elongation of the building footprint to maximize south façade area; and thermal mass (concrete slab, tile, stone) to absorb daytime solar energy and release it at night. Passive solar design reduces heating energy use by 20–50% at zero additional construction cost — but only when the orientation and overhang geometry are correct from the initial site plan. Passive solar is free at SD and essentially impossible to retrofit. RainFire Builders provides a solar orientation analysis for every new construction project at the programming phase.