Keystone is a National Fenestration Rating Council (NFRC) licensed Inspection Agency (IA). The NFRC Certification Program offers fenestration (window and door) manufacturers a third party verified, nationally-recognized method for demonstrating product U Factor, Solar Heat Gain Coefficient (SHGC) and other energy performance characteristics.

The Keystone Fenestration Certification Program is accredited by the ANSI National Accreditation Board (ANAB) and theStandards Council of Canada (SCC), providing fenestration manufacturers with a full slate of nationally-recognized product certifications for both the US and Canadian markets.
The Keystone Quality Assurance Program is accredited by the ANSI National Accreditation Board (ANAB), is officially recognized by the Florida Department of Business and Professional Regulation (DBPR) for demonstrating compliance with the third-party quality assurance requirements of the Florida State Product Approval Rule 9N-3 and ICC Evaluation Reports.