The quantifiable evidence of the economic impact of energy savings and productivity gains of passive solar or low-energy buildings and the whole buildings approach is impressive:

The West Bend Mutual Insurance Company built a 150,000 square-foot facility integrating the shell, interior design, and heating and cooling systems and “environmentally responsive” workstations. The result was a 40% reduction in energy consumption and a measured increase of 16% in claim-processing productivity as a result of employee appreciation of the building design and systems.

Lockheed Missiles and Space Company moved 2,700 employees to a new 600,000 square-foot facility that had been designed for energy efficiency, daylighting, and acoustic and visual comfort. The $2 million extra first cost was recouped in just four years from energy savings of $500,000 per year — but beyond that, a measured reduction in absenteeism of 15% is reported to have actually paid all costs back to Lockheed in the first year.

The Bullocks department store chain purchased a building in San Jose, California, and replaced one-quarter of the roof with translucent tensile fabric to use natural daylighting. The store found that sales in that section of the store increased by 15% regardless of what merchandise was put in that area.

Twenty-three $70,000 rowhouses were constructed in North Philadelphia combining energy efficiency with passive solar design. The reduction in energy use was 63% at no added construction costs.