Economics of Passive Solar - Arizona Solar Center - Your Guide to Solar and Other Renewable Energy Sources in Arizona

Economics of Passive Solar

Arizona has a variety of climates, largely determined by altitudes, which range from near sea level to over 11,000 ft. In the central and western sections of the state and most of the south, desert conditions prevail with high summer daylight temperatures and mild winters, although day-night variations are great. At higher elevations, mainly in the north and east-central mountains, winters are cold and summers mild.

Because the bulk of Arizona's population, including the large cites of Phoenix and Tucson, are located in the center and south, the information in this section is limited to these areas.

Passive solar construction cost vary from little if any more than conventional construction to considerably more. Many forms are economical because of the large savings of utility bills that can be achieved - typically in the 50% to 70% range. The Sustainable Energy Code developed in Tucson for the Civano Solar Village stipulates heating and cooling savings of 65% above the Model Energy Code. It is widely applicable elsewhere in the state. In addition, there are significant health benefits of living solar including an absence of pathogens in artificially cooled air and noise reduction.

Passive solar can utilize standard construction systems with careful space planning, orientation, selection of building systems placement, size of windows and selection of building materials (e.g. thermal mass). All of these entail little if any additional cost.

Costs will be greater if special materials are used such as rammed earth, straw bale, adobe construction with outsolation, poured-in-place adobe, water storage tubes, movable insulation, etc. In several of these, costs are high because demand is low. Cost could come down if mass production becomes feasible. Costs also are higher if expensive tile or brick is used for thermal mass floors or decorative block thermal mass walls, earth integration or custom fabrication parts, with the additional cost over standard construction usually in the 5-10% range.

In some instances, specialty items actually cost no more (or even slightly less) than conventional construction. For example, in one house a roof pond system was used for heating and cooling, replacing conventional roofing, roofing structure, heating system, cooling system and ductwork.

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