Building a Healthy Home: A Comparative Life-Cycle Analysis of Energy-Efficient and Low-VOC Retrofits

Abstract

As the main cause of death in America and the leading factor of increased health care costs, chronic illness is a growing concern. While several determinants influence the onset of disease, the surrounding environment, especially residential buildings, plays a significant role in overall health. The sustainable building industry emerged in response to growing concern around climate change, initially as a means to reduce energy use and the burning of fossil fuels. Over the years, it has evolved to include an emphasis on health and wellness, with the potential to mitigate the rising rates of chronic illness. This thesis compared certification requirements of three green building programs (WELL, LEED, Passive House) to identify differences that may impact health and should be prioritized in the retrofit of a conventional home to a greener home, all else equal. I hypothesized that (1) a retrofit of a conventional home that incorporated green building elements would result in a greater improvement (decrease) in Disability Adjusted Life Years (DALYs) compared to the conventional build and that (2) incorporation of low- VOC materials would result in the greatest improvement (decrease) in DALYS relative to the conventional build and the incorporation of an energy-efficient heat pump. I utilized SimaPro, the industry-leading life cycle analysis (LCA) software, to evaluate health impacts in terms of DALYs associated with the transition from a conventional model to (1) a Low-VOC Model and (2) an Energy-Efficient Model with a heat pump. Sensitivity analyses included (1) a Low-VOC Model with bamboo flooring, (2) a Low-VOC Model with hardwood flooring, and (3) a Combo Model with both low- VOC materials and a heat pump. Modeled as 1970’s home in New Jersey, USA, the Conventional Model was modified to incorporate green building elements associated with LEED v4.1 Certified, WELL v2 Certified, and Passive House Institute (i) 10.B guidelines. I collected an inventory of materials, sources and quantities, based on certification criteria within the green building programs, outputs from Athena Impact Estimator, and input from a NJ contractor active in the housing stock. Findings include that the Low-VOC Model and the Energy-Efficient Model reduced DALYs, with the greatest reduction from the Energy-Efficient Model. A sensitivity analysis indicated that the Low-VOC Model with bamboo flooring and the Low-VOC Model with hardwood flooring slightly reduced DALYs. The Combo Model reduced the most DALYs. Findings were scaled to represent 7%, 10%, 15%, 20%, 25%, 30%, 35%, and 40% of the NJ housing stock to illustrate the impact sustainable building elements could have across a state-wide scale. In addition to the growing arsenal of optimal building support tools, this thesis proposes practical retrofits for homeowners through LCA methodology. This research is timely, as the 2022 Inflation Reduction Act tax credits and rebates, intended to reduce carbon emissions through national building stock updates and have the potential to improve building health, will begin in 2024. Nevertheless, limitations to LCA methodology (e.g., sparse data on post-production emissions, lifetime material toxicity and associated occupant health impacts) prevent a full understanding of building health. Future improvements to LCA methodology and chemical material standardization would facilitate an ample, objective means to evaluate building health impacts of construction/retrofit activities.