C007 -- Modeling Cost Effective Applications of Window Attachments for Weatherization Programs

The U.S. Department of Energy (DOE) Weatherization Assistance Program (WAP) is a whole-house energy-efficiency program focused on reducing energy costs and burdens for low-income households. Throughout its 45-year history WAP has instituted auditing and evaluation tools to ensure maximum energy savings employing cost-effective approaches. The increasing occurrence of extreme weather events and persistent economic difficulties associated with the COVID-19 pandemic only increases the energy burden on low-income households, making it necessary for WAP to quickly adapt resources and tools to ensure that the latest and most effective energy-efficient and resilient envelope technologies can find their way into the list of approved WAP measures. Laboratory and field studies sponsored by the U.S Department of Energy (DOE) demonstrate that the installation of low-emissivity (low-e) storm windows over existing windows can provide many existing homes with a cost-effective, easy-to-install weatherization measure that improves air sealing, thermal insulation, occupant comfort, and envelope resilience. In this modeling study, we evaluate the energy and cost-effectiveness across a broad range of U.S. climate zones from the installation of low-e storm window attachments in manufactured homes using the Manufactured Home Energy Audit (MHEA) software, a WAP-developed audit tool. Low-e storm windows are found to be a cost-effective weatherization measure in most climate zones when installed over single-pane or double-pane clear glass windows and should be considered in weatherization efforts and included as viable measures in WAP resources and tools.