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Title: Building America Case Study: Sealed Crawl Spaces with Integrated Whole-House Ventilation in a Cold Climate, Ithaca, New York

"9One 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.
Publication Date:
OSTI Identifier:
Report Number(s):
NREL/FS-5500-64459; DOE/GO-102015-4700
DOE Contract Number:
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (EE-5B)
Country of Publication:
United States
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; Crawlspace; Ventilation; Whole-house ventilation; Exhaust-only ventilation; Radon; Code compliance; IRC; International Residential Code: ASHRAE 62.2; ASHRAE 62.2-2010; ASHRAE 62.2-2013; Tracer gas; SF6; Reciprocal Age of Air; RAoA; CARB; Consortium for Advanced Residential Buildings; SWA; Steven Winter Associates; Condensation potential; Dewpoint; Sealed crawlspace; Unvented crawlspace; Residentia