Paul Milligan'sHVACSuite is a new program that combines a powerful group of free tools with economy-priced "pay to register" modules. The free tools include psychrometrics, equal friction duct calculations, and more, while the "pay to register" modules include an advanced duct calculator for metal, flex, and ductboard ducts, HVACR system analysis linked to a database of 38 refrigerants, database-driven job estimating, and more. Free download is available