TheLEED for Homes Rating System (v4)includes theEnergy and Atmosphere (EA) Credit: Windows, which sets performance requirements for windows to balance energy efficiency with design goals, such as large glazing areas for views. Higher window-to-wall ratios require more stringent performance to mitigate heat loss or gain.
According to theLEED Reference Guide for Homes Design and Construction (v4):
EA Credit: Windows (1–3 points)
Meet the prescriptive window performance requirements based on the window-to-exterior wall area ratio (WWR). If the WWR exceeds 24%, more stringent U-factor and solar heat gain coefficient (SHGC) values are required to ensure energy efficiency.
Source: LEED Reference Guide for Homes Design and Construction, v4, Energy and Atmosphere Credit: Windows, p. 122.
TheLEED v4.1 Residential BD+Crating system confirms:
EA Credit: Windows
For projects with a window-to-exterior wall area ratio greater than 24%, windows must meet enhanced performance criteria (e.g., lower U-factor and SHGC) to reduce energy losses.
Source: LEED v4.1 Residential BD+C, Credit Library, accessed via USGBC LEED Online.
The correct answer iswindow-to-exterior wall area ratio is greater than 24%(Option C), as this triggers stricter window performance requirements to maintain energy efficiency.
Why not the other options?
[Reference: LEED Reference Guide for Homes Design and Construction, v4, EA Credit: Windows, p. 122., B. Window-to-floor area ratio is greater than 15%: The credit uses window-to-exterior wall ratio, not window-to-floor ratio, for performance criteria.Reference: LEED Reference Guide for Homes Design and Construction, v4, EA Credit: Windows, p. 122., D. Window-to-floor area ratio is greater than 24%: The credit does not reference window-to-floor ratio; the 24% threshold applies to window-to-wall ratio.Reference: LEED Reference Guide for Homes Design and Construction, v4, EA Credit: Windows, p. 122., TheLEED AP Homes Candidate Handbookemphasizes EA credits, including window performance, and references theLEED Reference Guide for Homes Design and Constructionas a key resource. The exam is based onLEED v4, ensuring the relevance of the 24% WWR threshold., References:, LEED Reference Guide for Homes Design and Construction, v4, USGBC, Energy and Atmosphere Credit: Windows, p. 122., LEED v4.1 Residential BD+C, USGBC LEED Credit Library, accessed via USGBC LEED Online (https://www.usgbc.org/credits)., LEED AP Homes Candidate Handbook, GBCI, October 2024, p. 12 (references study resources and exam scope based on LEED v4)., USGBC LEED for Homes Rating System (v4), available via USGBC website (https://www.usgbc.org/resources/leed-homes-design-and-construction-v4)., LEED v4.1 for Homes, USGBC, accessed via LEED Online, confirming window performance criteria., ]
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