HVAC ducts can be best described as arteries of the central air-conditioning system. These play an important role in keeping the whole HVAC system fit and achieving comfortable conditions throughout its life span. Defects in a duct system can waste hundreds of dollars a year by forcing your HVAC system to run longer than necessary. Ductwork problems also make certain rooms too hot or too cold at different times of the year, while introducing dirt and bad odors into your forced-air system. This book is a short course on HVAC duct design and fundamentals. The book includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course content.