LEED Sustainable Sites and Indoor Environmental Quality Criteria in a LEED Gold-Certified Hospital: A Post-Occupancy Evaluation of Occupant Satisfaction

Technical Summary: LEED Sustainable Sites and Indoor Environmental Quality Criteria in a LEED Gold-Certified Hospital

Problem Statement
Healthcare facilities are among the most resource-intensive building types, necessitating verifiable sustainability standards. While LEED certification is the dominant global framework for assessing sustainability, evidence regarding its correlation with actual occupant satisfaction—particularly in healthcare settings—remains limited. Existing literature suggests that green building scorecards often reflect design-stage intentions rather than post-occupancy performance. Specifically, there is a gap in research directly comparing specific LEED credits in the Sustainable Sites (SS) and Indoor Environmental Quality (IEQ) categories with the lived experiences of hospital occupants. This disconnect is critical because SS and IEQ criteria govern the immediate daily interactions of staff and patients, yet they are awarded primarily based on design documentation and specification compliance rather than in-use performance or user feedback.

Methodology
This study employed a single-case, credit-matched comparative design to investigate the relationship between LEED-certified performance and occupant-reported satisfaction at Başakşehir Çam and Sakura City Hospital in Istanbul, Türkiye. This facility is a LEED Gold-certified complex (63/110 points) with over 2,600 beds and approximately 1,000,000 m² of floor area.

The research utilized two complementary data sources:

1. Documentary Analysis: A review of the hospital's official LEED BD+C: Healthcare scorecard to identify achieved credits within the SS and IEQ categories.
2. Occupant Survey: A structured, interviewer-administered questionnaire conducted in February 2025 with a convenience sample of 100 healthcare professionals (including physicians, nurses, administrative staff, and support personnel).

The survey focused on SS and IEQ criteria, as these encompass the aspects of building performance most directly experienced by users (e.g., transportation access, outdoor amenities, ventilation, thermal comfort, lighting, and acoustics). Responses were collected using a three-point Likert scale (Yes/Adequate, Undecided/Partially Adequate, No/Inadequate).

Data analysis involved systematically mapping survey items to corresponding LEED credits. Responses were categorized into three states:

• Agreement: Both LEED certification and occupant perception indicate adequate performance.
• Mismatch (LEED Positive/Perception Negative): A credit was achieved, but occupants perceived the feature as inadequate.
• Mismatch (LEED Negative/Perception Positive): No credit was achieved, but occupants perceived the feature as adequate.

Key Results
The study revealed notable discrepancies between certification achievements and occupant perceptions, often showing an inverse pattern where high credit achievement did not guarantee satisfaction, and low credit achievement did not preclude it.

• Sustainable Sites (SS):

  • Agreement: Occupants and LEED scores aligned on public transportation access, proximity to transit stops, and the adequacy of parking facilities.
  • Mismatch (LEED Positive/Perception Negative): Despite achieving credits for alternative transportation, 71% of respondents found electric vehicle (EV) charging stations inadequate. Similarly, 44% rated the overall location accessibility as inadequate, and 62% found surrounding pedestrian and cycling infrastructure inadequate, despite relevant credits being earned.
  • Mismatch (LEED Negative/Perception Positive): The hospital garden area received no specific LEED credit, yet 71% of respondents rated it as adequate.

• Indoor Environmental Quality (IEQ):

  • Agreement: High satisfaction was reported for air quality (83%), ventilation (71% reported never experiencing stuffiness), and smoking area placement. Thermal comfort and system controllability also showed alignment between achieved credits and user satisfaction.
  • Mismatch (LEED Negative/Perception Positive): Despite limited or absent LEED credits for daylight and visual connection, occupants reported high satisfaction with natural light availability (92%), daylight adequacy (83%), and the positive impact of outdoor views on work motivation (73%).
  • Mismatch (LEED Positive/Negative Perception): While low-emitting materials credits were not fully achieved, 62% of respondents reported experiencing odors from paint, adhesives, or cleaning products, indicating a gap between material specifications and operational reality. Acoustic performance was mixed, with 54% reporting noise-related difficulties in concentration or communication, despite the absence of specific acoustic credits in the scorecard.

• Awareness: Only 54% of respondents were aware of the hospital's LEED certification status, suggesting that occupant evaluations are driven by direct daily experience rather than formal certification knowledge.

Key Contributions
This study contributes to the limited body of research on green building certification and post-occupancy performance in healthcare facilities by providing a granular, credit-level comparison between certification outcomes and occupant perceptions. It demonstrates that LEED certification, while valuable for establishing design intent and technical compliance, does not fully capture the nuances of occupant satisfaction. The findings highlight that specific infrastructure and environmental features (such as EV charging, pedestrian pathways, and daylighting) may be evaluated differently by users than by certification protocols.

Significance and Claims
The authors claim that the divergence between LEED scores and occupant experience indicates that certification outcomes and user experience represent different dimensions of building performance. The study suggests that LEED credits, awarded based on design-stage documentation, may not ensure that infrastructure supports the intense, continuous operational demands of large healthcare campuses. Conversely, architectural features that deliver significant experiential value (such as visual connections to nature) may perform well for users even without corresponding LEED points.

The paper concludes that sustainable healthcare facilities are best evaluated through a hybrid approach combining technical certification with systematic post-occupancy evaluation (POE). Integrating systematic feedback into certification and operational processes is proposed as a method to promote more user-centered sustainable healthcare environments. The authors modestly note that these findings are based on a single case study and call for future research across multiple facilities and certification levels to generalize these insights.