Secondary Author(s)

Cummings, James; Lahiff, Ian

Report Number




Air Flow; Buildings; Wind; Peak Demand


Wind washing has been identified as a potentially significant issue regarding energy, demand, comfort, and humidity in some two-story Florida homes. In its most common configuration, wind washing occurs when attic spaces over first-floor portions of the home abut the second story, and the floor cavity of the second story is open to that attic space. Wind blowing into attic vents can push hot attic air into the inter-story floor cavity, bypassing the typical thermal boundaries of the building and introducing considerable heat into the house. Wind washing can also occur when there is little or no attic involved, where outdoor air can infiltrate directly into the floor cavities. Phase 1 of a study to identify these air flow failures and possible insulation system failures in adjacent knee walls has been completed. Field testing has been completed in 32 homes and monitoring and repair has been implemented in six homes. Significant wind washing potential has been found in about 40% of the tested homes. Relatively few knee wall insulation problems have been identified, though it is common for knee walls facing into attic spaces to have effective R-values of less than 10. Monitoring of temperature, humidity, and AC energy consumption in six homes was implemented for about two months, repairs were implemented, monitoring continued for about 6 to 8 weeks after repair. Energy and peak demand analysis was implemented. Annual cooling energy savings averaged 15.3% and peak demand savings averaged 12.6% for these six homes. Because the wind washing potential identified in the six repaired homes was less than other homes tested later, the research team believes that these cooling energy and demand savings are less than might otherwise be found.

Date Published


Local Subjects

Buildings - Air Flow; Buildings - Peak Demand; Wind


FSEC Energy Research Center® Collection



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