December 19, 2006

A design process is described for sizing cooling and heating system capacity, for specifying the airflow and duct sizes to each conditioned space, and for specifying the free area needed to transfer air supplied to closed rooms back to the central return. This design process involves using a computerized version of the industry standard ACCA Manual J calculation procedure, with specific parameters specified to properly handle infiltration, ventilation, glazing, and airflow velocities for ducts.