Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

A. Rudd, D. Bergey

Research output: NRELSubcontract Report


Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow.Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.
Original languageAmerican English
Number of pages100
StatePublished - 2014

Bibliographical note

Work performed by the Building Science Corporation, Somerville, Massachusetts

NREL Publication Number

  • NREL/SR-5500-61128

Other Report Number

  • DOE/GO-102014-4362


  • airborne particles
  • BSC
  • Building America
  • formaldehyde
  • indoor air quality
  • particulate
  • particulate matter (PM)
  • residential
  • residential buildings
  • TVOC
  • ventilation
  • ventilation air distribution
  • ventilation air source
  • ventilation effectiveness
  • ventilation system factors
  • VOC
  • volatile organic compounds (VOC)
  • whole-building ventilation


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