The health and indoor environmental quality impacts of residential building envelope retrofits: A literature review

Retrofitting existing buildings to improve energy efficiency is an important strategy to meet increasingly strin- gent energy efficiency targets. While the primary objective of energy efficiency retrofits is to reduce energy consumption and greenhouse gas emissions, retrofits can also result in non-energy impacts (NEIs), which contribute to decision-making processes and overall value of the retrofit. NEIs have been studied extensively in retrofitted residential buildings; however, these studies have historically grouped passive (i.e., building enve- lope) and active (i.e., heating, ventilation, and air conditioning (HVAC) and energy system) upgrades, making it difficult to identify the underlying mechanism(s) of action for each NEI and developing effective retrofit stra- tegies, based on occupant need. The purpose of this study was to better account for NEIs, based on a literature review, summarizing the current state of knowledge on NEIs associated with residential building envelope ret- rofits. We limited our search to health- and indoor environmental quality-related NEIs. The review identified strong evidence that building envelope retrofits improve acoustic comfort, wintertime thermal comfort, and respiratory and cardiovascular health outcomes. IAQ outcomes were mixed, with studies reporting both increases and decreases to indoor contaminant concentrations following retrofits. The strength of the effect was generally governed by pre-retrofit contaminant concentrations and whether indoor concentrations were dominated by indoor or outdoor sources. Most studies evaluating summertime thermal comfort identified increased incidence of summertime overheating; however, none of these studies linked the change in thermal conditions to health outcomes. Recommendations for future work include expanding studies to include more market rate housing and the health impacts of summertime overheating in retrofitted buildings.