ATLANTA - The energy efficiency of different residential HVAC systems can be evaluated in the design or retrofit stages using a new method from the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).

Users can demonstrate the benefits of better duct sealing and improved insulation and size equipment accordingly, according to Standard 152 committee chair Mark Modera. "Field studies have shown that sealing and insulating ducts in existing homes can result in energy savings of 10 to 35 percent," he said.

ANSI/ASHRAE Standard 152, "Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Systems," is designed to evaluate energy inefficiencies and estimate energy savings, as well as aid in equipment sizing. According to Modera, the standard allows direct comparisons such as hydronic vs. air systems, as well as comparisons of air systems with different levels of duct leakage and insulation, he said.