Site planning in hot-arid regions has three primary objectives: The first is maximizing shade in the late morning and all afternoon. This is especially important for outdoor living areas. The second is to maximize humidity, and the third is maximizing summer air movement.
To accomplish these, the best orientation is generally 25 degrees south-southeast. Position the home low for cool air flow. Lower hillside sites will receive cooler natural air movement during early morning and warm air movement during early evening. Locate living areas in the south and southeast portion of the home, leaving the north side for inactive areas like garages and storage rooms. When possible to locate near a lake, stream, or other body of water, site the home on the lee side to take advantage of the cooling effects of evaporation. Both indoor and outdoor activity areas will benefit from cooling breezes that increase humidity levels and lower temperatures.
Outdoor living areas should be located to the southeast of the dwelling to take advantage of early morning sun and the shade provided in the afternoon by the structure itself.
South-facing exterior walls and windows will allow winter sun to warm the building. In summer they should be shaded either by roof overhangs or by deciduous vines or trees to limit excessive solar radiation into the home. Keep windows on the east and west sides of the home small to reduce heat gain into the house in early morning and late afternoons.
Excessive glare and re-radiation from the outdoor environment can be reduced by providing shaded parking areas or carports, grass around the home, and an east-west orientation of a narrow roadway. Keep building materials light in color to reflect the sun.
In hot, arid regions, tight construction will minimize heating and cooling requirements, and properly sized air conditioners will optimize cooling performance.