The building is prefabricated in three easily transportable modules, reducing initial cost and energy, and facilitating efficient relocation and reuse in the future, minimizing waste. A steel frame and steel and rigid foam, sandwich panel floor and roof system minimize material use; maximize insulation and heat reflection; and deter pests and mold in the cavity-free structure. A simple, double wall metal cladding, along with metal roofing shaded by solar panels above a 3” ventilated airspace, creates a ventilated double skin greatly reducing heat gain. All glazing is operable and north facing and/or shaded to prevent direct sunlight, and to optimize natural ventilation and comfortable airflow. Interior surfaces are low VOC products. Exposed beams are FSC certified glue-laminated timbers combined with steel trusses to visibly trace primary structural forces. Interior surfaces are naturally finished, low VOC materials to provide good interior air quality. Daylighting analysis indicates that excellent work light levels are achieved throughout the typical school day in most locations without electric lighting. Thermal comfort analysis indicates the classroom will be comfortable in most high heat climates without air conditioning, although an efficient mechanical air conditioning system is also available as an option for school sites where air quality or noise conditions preclude natural ventilation.