As part of the Jackson Laboratory's Energy Master Plan, it was decided to abandon an old, energy-intensive building used for rearing experimental animals and construct a new energy efficient facility. A pre-engineered metal structure was selected for lower unit costs and for rapidity of construction. Sprayed on polyurethane insulation was applied to reduce building heat losses to an acceptable level. Laboratory personnel designed an energy system to provide high volumes of air exchange utilizing an integral, site built air-to-air solar collection wall in series with an air-to-air heat exchanger to handle about 4,500 cubic feet of air per minute. Rigid environmental standards for the rearing space presented additional challenges in the design. No thermal storage was incorporated in the original design but plans call for installing such storage in additional modules of the building.