Overheating Buildings in Coastal Communities: Homes, Health Impacts, and Opportunities for Collaboration in San Francisco

The San Francisco Department of Public Health Program on Health, Equity, and Sustainability, conducted a health impact assessment (HIA) to address increased heat vulnerability of coastal communities and overheating problems in a high-rise condominium building in San Francisco, California. The HIA focuses on how modern building trends, such as open-floor concepts and floor-to-ceiling windows, may increase heat vulnerability if compensatory cooling design elements are not also included in the building design. Due to the lack of official heat-related illness data, the project team conducted interviews, used San Francisco 311 complaint log data, analyzed publicly available data and user experiences on social media sites, and conducted a literature review.

The HIA found that residential buildings or housing codes in California do not yet provide an enforceable standard for maximum indoor temperatures but professional standards issued by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) dictate that the maximum indoor temperature should not be greater than 78-82 degrees Fahrenheit in the summer, depending on humidity. The HIA found that while high temperatures in the city of San Francisco ranged between 67 and 81 degrees Fahrenheit in September 2010, some units in a high-rise condominium building experienced indoor temperatures exceeding 90 degrees Fahrenheit for more than seven consecutive hours over a 3-day period.

The HIA recommended building design elements, such as purge ventilation and ceiling fans, and regulatory and/or code-based solutions and enforcement as part of a comprehensive strategy to mitigate the adverse effects of overheating in buildings.

This HIA was funded by the Centers for Disease Control and Prevention.