Building America Case Study: Air Leakage and Air Transfer Between Garage and Living Space, Waldorf, Maryland

Stacey Rothgeb, A. Rudd, H. Loomis

Research output: NRELFact Sheet


This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.
Original languageAmerican English
Number of pages2
StatePublished - 2014

Bibliographical note

Work performed by Building Science Corporation (BSC), Somerville, Massachusetts

NREL Publication Number

  • NREL/FS-5500-62574

Other Report Number

  • DOE/GO-102014-4490


  • air leakage
  • attached garage ventilation
  • blower door testing
  • BSC
  • Building America
  • garage air leakage
  • garage testing
  • garage-to-house air leakage
  • indoor air quality
  • residential
  • residential buildings
  • whole house ventilation


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