Secondary Author(s)
Withers Jr., Charles
Report Number
FSEC-RR-140-06
URL
http://publications.energyresearch.ucf.edu/wp-content/uploads/2018/06/FSEC-RR-140-06.pdf
Keywords
Buildings; Ducts; HVAC
Abstract
Field research performed in 70 central Florida homes found that return grills are almost always located in the central zone of the house, and that individual rooms rarely have ducted return air or return transfer pathways. When interior doors were closed, the closed rooms went to +0.0249 inches of water gauge (in w.g.) (+6.2 pascals (Pa)) wrt outdoors (wrt = with respect to), and the central zone went to -0.0116 in w.g. (-2.9 Pa) wrt outdoors. Room pressures as high as +0.150 in w.g. (+37.3 Pa) and central zone pressure as low as -0.059 in w.g. (-14.7 Pa) wrt outdoors were found. These pressures create exfiltration from the closed rooms and infiltration in the central zone. With the air handler operating, the house infiltration rates increased, on average, from 0.46 to 0.60 air changes per hour when all interior doors were closed. According to homeowner reports, interior doors are closed 11% of the time, on average. These pressures and increased infiltration rates impact indoor air quality, indoor relative humidity, energy use, peak electrical demand, comfort, and system sizing.
Date Published
1-1-2006
Subjects
Buildings - Ducts; Buildings - HVAC
STARS Citation
Florida Solar Energy Center and Cummings, James, "Unbalanced Return Air In Residences: Causes, Consequences, And Solutions" (2006). FSEC Energy Research Center®. 511.
https://stars.library.ucf.edu/fsec/511
Notes
Reference Publication: James B. Cummings and Charles R. Withers, Jr.. "Unbalanced Return Air in Residences: Causes, Consequences, and Solutions". ASHRAE Transactions Vol 112, Part 1, January 2006.