Comparative Cooling Season Performance of Air Distribution Systems in Multistory Townhomes

Stacey Rothgeb, A. Poerschke, R. Beach, T. Beggs, Stacey Rothgeb (NREL Technical Monitor)

Research output: NRELSubcontract Report


IBACOS investigated the performance of a small-diameter high velocity heat pump system compared to a conventional system in a new construction triplex townhouse. A ductless heat pump system also was installed for comparison, but the homebuyer backed out because of aesthetic concerns about that system. In total, two buildings, having identical solar orientation and comprised of six townhomes, were monitored for comfort and energy performance. Results show that the small-diameter system provides more uniform temperatures from floor to floor in the three-story townhome. No clear energy consumption benefit was observed from either system. The builder is continuing to explore the small-diameter system as its new standard system to provide better comfort and indoor air quality. The homebuilder also explored the possibility of shifting its townhome product to meet the U.S. Department of Energy Challenge Home National Program Requirements. Ultimately, the builder decided that adoption of these practices would be too disruptive midstream in the construction cycle. However, the townhomes met the ENERGY STAR Version 3.0 program requirements.
Original languageAmerican English
Number of pages56
StatePublished - 2016

Bibliographical note

Work performed by IBACOS, Inc., Pittsburgh, Pennsylvania

NREL Publication Number

  • NREL/SR-5500-65315

Other Report Number

  • DOE/GO-102016-4803


  • air conditioning
  • air distribution system
  • Building America
  • comfort
  • ductless mini-split heat pumps
  • heating, ventilation, and air conditioning (HVAC)
  • high velocity ducts
  • residential
  • Residential Buildings
  • small-diameter ductwork
  • stratification
  • townhome


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