A prevalent residential building type in older cities, rowhouses are an especially challenging form of housing to adapt for cooling performance in a way which does not reinforce the feedback loop between building emissions and climate change. If existing homes are not equipped with sufficient air-conditioning systems or if residents can’t afford to run air-conditioning units to keep up with the heat, residents face health risks such as heat-related illnesses and mortality. Some neighborhoods within a city are hotter than others due to the historically uneven, inequitable distribution of heat-absorbing hardscape and naturally cooling landscape throughout the city, so these communities are even less equipped to find relief in extreme heat events. This thesis aims to identify effective, affordable, and compatible passive design strategies for rowhouses that reduce heat gain and building emissions. To that end, this study began by modeling existing blocks of rowhouses within the Strawberry Mansion neighborhood of Philadelphia for building simulation studies that look at the amount of direct sun, solar radiation, and natural ventilation the rowhouses receive at the whole block level. After the initial block studies, an individual rowhouse representing the most challenging condition for cooling was identified as the base case for a more in-depth study. The results of the existing conditions informed nine passive design strategies selected for subsequent studies in order to evaluate and compare each strategy’s effectiveness in reducing heat gain and level of impact to the original building. Studies conducted at the roof, exterior windows, and exterior walls were further divided into three distinct intervention types to help homeowners and policymakers prioritize passive design strategies over cost- and energy-intensive mechanical upgrades in the future. The methodology of this study was designed to analyze local environmental factors—both natural and constructed—that contribute to overheating within the rowhouse in order to create a framework for further adaptation planning that are derived from local climate, site conditions, and building characteristics.