CH-24-C038 - Prefabricated R30 Retrofit Panel Development and Verification

Buildings are the largest consumers of energy in the United States (U.S.), with significant portions of residential building stock predating the building energy codes or having been built with low levels of envelope insulation. Envelope retrofits are an urgent need for residential buildings across the U.S. However, current retrofit solutions, whether drill-and-fill interior solutions or exterior continuous insulation solutions, are labor intensive and disruptive. Exterior insulation systems of R6/inch or less need substantial thicknesses for meaningful improvement in the envelope performance, resulting in disruptive structural changes. Deep energy envelope retrofits of homes are rarely undertaken even though envelope retrofits are one of the most effective methods to improve occupant comfort and reduce energy consumption. This article describes the development of an easy-to-install, highly efficient, customizable and prefabricated wall retrofit solution for residential buildings. The design and prefabrication process will be aided by 3D scanning and digital modeling of the building façade. Further downstream, the installation of the retrofit panels will be facilitated by augmented reality. The key innovations are the use of vacuum insulation panels (VIPs) and 3D scanning and modeling of the building enclosure for custom design and fabrication of the retrofit panels. The retrofit technology will incorporate VIPs into an existing and commercially available expanded polystyrene (EPS) panel with built-in plastic studs. The EPS-VIP panels can achieve R30 within 3-4 inches. The thin profile helps in space constrained applications. A method for large-scale prefabrication of the retrofit system in a factory environment is described. The panels are designed to be installed without any on-site customization and associated waste. The exterior retrofit will be minimally intrusive and can occur in one week or less. The nominally 4’x2’ or smaller retrofit panels will be small enough to be installed manually without a need for cranes, which can significantly reduce installation complexity and costs. Finally, the article will describe the development and testing of prototype EPS-VIP panels to verify that R30 can be achieved within a 3-4” thickness.