Low Cost Interior Duct Systems For High Performance Homes In Hot Climates

The advantages of well designed and constructed interior duct systems are numerous. Among these advantages is improved energy efficiency through the elimination of duct leakage to outside and the elimination of conductive heat gains/losses. Occupant comfort is improved because conditioned air that remains in the ducts after the mechanical system has reached the set point temperature is not being impacted by temperatures in the attic. This method eliminates hot /cold air blows at equipment startup. Interior duct systems result in improved indoor air quality due to elimination of duct leaks. The use of a passive return air strategy eliminates return air ducting in the attic. The elimination of this source of induced infiltration leads to improved indoor air quality (IAQ) and reduces material and labor costs. Opportunities are created due to a variation of different ceiling heights, dropped ceiling and soffits to accommodate the distribution system that improve aesthetics. Consequently this method is best suited to new construction when design choices can be significantly impacted. This measure will only present one opportunity to be implemented in the life cycle of the home but once implemented will last the life of the dwelling. While the advantages of well designed and constructed interior duct systems are recognized, the implementation of this approach has not gained a significant market acceptance. Homes in hot climates are still typically designed and built with duct systems in the attic. This paper presents a cost effective method that was used by four builders in the Gainesville, FL area to construct interior ducts in over a dozen site built homes