WINDOW CONDENSATION The Learning Center The National Fenestration Rating Council (NFRC) developed a methodology for determining condensation formation on the inside surfaces of windows. It should be noted that in the real world, environmental conditions, which will affect a product’s performance, vary from the standardized environmental conditions used to determine Condensation Resistance. As a result, the NFRC 500 standard is not meant to predict condensation; rather it is meant to be a tool for rating and comparing window products and their potential for condensation formation. Condensation Resistance (CR) measures how well a product resists the formation of condensation.  CR is expressed as a number between 1 and 100.  The higher the number, the better a product is able to resist condensation. A precursor to the NFRC standard was the American Architectural manufacturers Association (AAMA) Standard 1502.3, which is a test method and standard developed to evaluate the relative condensation performance of windows and doors under a set of typical conditions. The AAMA CRF test method has been in existence for nearly 30 years.  The CRF is primarily intended for comparative analysis of similar products, however, it is also a valuable means to project when and where condensation will occur on a fenestration product. The CRF is a numerical index generally in the range of 30 – 80 for conventionally glazed fenestration products. The larger the CRF number, the greater the resistance to condensation. In the past, AAMA defined a CRF rating of 35 as the minimum for a thermally improved window or door. The CRF for the product is determined by the lower of either the weighted frame temperature or the average glazing temperature.               16. What is Condensation Resistance Factor (CRF)? < back to list of questions about window condensation 1-877-SWING CLEAN info@energyswingwindows.com 3245 Miracle Drive Murrysville, PA 15668 724-387-2991 PA Contractor ID PA001856