Retrofitting existing wall cladding, or re-siding, occurs on approximately 2 million homes per year in America. In most cases, exterior continuous insulation or a rainscreen drainage system is not included in these retrofits. This is likely due to the higher incremental cost of these additional layers, the added labor effort, or lack of experience or skill on proper installation practices and integration with the siding. As a more energy efficient option, there are a few vinyl siding manufacturers that have incorporated a small amount of expanded polystyrene (EPS) foam to the back of the siding; however, this foam varies in thickness due to the profile of the siding and provides as average weighted R-value of approximately R-2.5 R-3. This siding is not widely used due to the minimal thermal improvement and the premium cost associated with the product. The proposed technology for this SBIR Phase I development project utilizes a commercially available and widely used engineered wood siding product with an integrated insulation material to provide a minimum of R-5 insulation R-value. The proposed technology can incorporate either a 1 thick, R-5 extruded polystyrene (XPS), 1 of R-6.5 polyisocyanurate, or 1 of R-5 graphite polystyrene (GPS) rigid board insulation with 3/16 grooves routed out on one side to provide an integral rainscreen, for a total combined product thickness of less than 1.5. The rigid insulation is laminated to the pre-finished engineered wood siding product. The insulation board and wood siding panels will be designed and cut out with very specific overlaps and seals at all edges that will provide a water and air barrier between all joints of the siding application. This integrated, installer friendly retrofit wall panel system incorporates integrated layers for cladding, thermal resistance, vapor retardance, and water drainage into one product for improved performance, installer productivity and cost. Adding R-5 continuous exterior insulation during siding replacement could provide primary energy savings of 7.7 TWh/yr with a simple payback period (SPP) of 4.4 yr. The technical development work will include proof of concept models and prototypes with full scale mockups to evaluate ease of installation, thermal performance, aesthetic appeal, and preliminary costing estimates. Additional effort will focus on customer discovery and identifying and developing partnerships to continue product development and quickly scale production and deployment across North America.
