Sealed Crawl Spaces with Integrated Whole-House Ventilation in a Cold Climate

Timothy Merrigan, William Zoeller, James Williamson, Srikanth Puttagunta, Stacey Rothgeb (NREL Technical Monitor)

Research output: NRELSubcontract Report


One method of code-compliance for crawlspaces is to seal and insulate the crawlspace, rather than venting to the outdoors. However, codes require mechanical ventilation; either via conditioned supply air from the HVAC system, or a continuous exhaust ventilation strategy. As the CARB's building partner, Ithaca Neighborhood Housing Services, intended to use the unvented crawlspace in a recent development, CARB was interested in investigating a hybrid ventilation method that includes the exhaust air from the crawlspace as a portion of an ASHRAE 62.2 compliant whole-house ventilation strategy. This hybrid ventilation method was evaluated through a series of long-term monitoring tests that observed temperature, humidity, and pressure conditions through the home and crawlspace. Additionally, CARB worked with NREL to perform multi-point tracer gas testing on six separate ventilation strategies - varying portions of 62.2 required flow supplied by the crawlspace fan and an upstairs bathroom fan. The intent of the tracer gas testing was to identify effective Reciprocal Age of Air (RAoA), which is equivalent to the air change rate in well-mixed zones, for each strategy while characterizing localized infiltration rates in several areas of the home.
Original languageAmerican English
Number of pages33
StatePublished - 2015

Bibliographical note

Work performed by Consortium for Advanced Residential Buildings, Norwalk, Connecticut

NREL Publication Number

  • NREL/SR-5500-64458

Other Report Number

  • DOE/GO-102015-4699


  • ASHARAE 62.2-2010
  • ASHRAE 62.2
  • ASHRAE 62.2-2013
  • code compliance
  • condensation potential
  • consortium for advanced residential buildings
  • crawlspace
  • dewpoint
  • exhaust-only ventilation
  • international residential code
  • IRC
  • radon
  • RAoA
  • reciprocal age of air
  • sealed crawlspace
  • SF6
  • Steven Winter Associates, Inc.
  • SWA
  • tracer gas
  • unvented crawlspace
  • ventilation
  • whole-house ventilation


Dive into the research topics of 'Sealed Crawl Spaces with Integrated Whole-House Ventilation in a Cold Climate'. Together they form a unique fingerprint.

Cite this