Report Number




Wind; Air Flow; Buildings


Wind washing is a general term referring to diminished thermal control caused by air movement partially or completely bypassing the thermal barrier. The primary focus of this paper relates to a specific type of wind washing where wind can push attic air into the floor cavity between first and second stories of the home through ineffective (or missing) air barriers separating attic space from the floor cavity. A second type of wind washing studied in this project involves insulation batts on knee walls where space between the batts and the wall board allow air movement against the gypsum wall board. Through the summer of 2009, a field study tested thirty-two homes and found significant wind washing potential in 40% of the homes as discussed in Part I of this paper. Repairs and energy monitoring were completed in six of these homes to evaluate retrofit methods and cost effectiveness of retrofit solutions. These results are discussed here in Part II of this paper. This paper reports average cooling energy savings measured in six homes of 15.3%. Savings were as high as 33.1% in one home. The paper also assesses the scope of these envelope problems, discusses improvements in comfort and durability, recommends retrofit solutions, and identifies energy savings potential for retrofit programs. While energy savings were only evaluated during summer weather, wind washing repairs should save energy during cold weather and be applicable throughout the nation

Date Published



Original Publication: Withers, C. and Cummings, J. “Opportunities for Energy Conservation and Improved Comfort From Wind Washing Retrofits in Two-Story Homes – Part II”, Seventeenth Symposium on Improving Building Systems in Hot and Humid Climates, August 24, 2010, in Austin, TX

Local Subjects

Buildings - Air Flow; Wind


FSEC Energy Research Center® Collection



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In Copyright