AHRI Standards 1350 (I-P) and 1351 (SI), “Mechanical Performance Rating of Central Station Air-handling Unit Casings,” were published the week of Dec. 1 and will serve as the rating standards for the new AHUC certification program. When paired with AHRI’s existing Central Station Air-handling Unit Supply Fan, Forced Circulation Air-cooling & Air-heating Coils, and Air-to-Air Energy Recovery Ventilators certification programs, the new program can help ensure the overall performance of an air-handling unit. The AHUC program will verify casing deflection and casing air leakage and has the option of verifying thermal transmittance with leakage, thermal transmittance without leakage, and thermal bridging.