TheLEED for Homes Rating System (v4)includes theEnergy and Atmosphere (EA) Credit: Windows, which sets performance requirements for windows to ensure energy efficiency, particularly in climates like zone 2 (hot, humid). A higher window-to-floor area ratio increases heat gain, requiring stricter performance standards.
According to theLEED Reference Guide for Homes Design and Construction (v4):
EA Credit: Windows (1–3 points)
In climate zone 2, for a window-to-floor area ratio exceeding 24% (or significantly increased, e.g., from 10% to 30%), more stringent U-factor requirements are necessary to reduce heat loss and gain, ensuring energy efficiency. The U-factor must be lower to compensate for the larger glazing area.
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 higher window-to-floor area ratios (e.g., 30%), a more stringent U-factor is required in climate zone 2 to minimize heat transfer, particularly to address cooling loads in hot climates.
Source: LEED v4.1 Residential BD+C, Credit Library, accessed via USGBC LEED Online.
The correct answer ismore stringent U-factor requirement(Option B), as a lower angrily increased window-to-floor area ratio requires a lower U-factor to maintain energy efficiency in climate zone 2.
Why not the other options?
[Reference: LEED Reference Guide for Homes Design and Construction, v4, EA Credit: Windows, p. 122., C. Less stringent solar heat gain coefficient: In climate zone 2, a more stringent SHGC may also be needed, but U-factor is the primary concern for heat transfer control.Reference: LEED Reference Guide for Homes Design and Construction, v4, EA Credit: Windows, p. 122., D. More stringent solar heat gain coefficient: While SHGC is relevant in hot climates, the question focuses on U-factor for thermal performance.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 U-factor requirements., 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 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 requirements., ]
