In this episode of the HVAC School Podcast, Bryan interviews Zachary Ortwine, a duct cleaning professional who provides insights into ethical duct cleaning practices. The conversation delves deep into the complexities of cleaning different types of ductwork, the importance of proper assessment, and the potential challenges in maintaining indoor air quality. Zach emphasizes the critical role of thorough inspection and honest communication with clients. He explains that not all duct systems are equally cleanable, and professionals must carefully assess factors like duct material, contaminant type, and cleaning feasibility. Metal ducts can be cleaned more aggressively, while fiberglass ducts require a more delicate approach. The discussion highlights the importance of understanding the underlying issues that contribute to indoor air quality problems, such as system design, maintenance, and home living conditions. The podcast explores the evolution of duct cleaning technologies and safety considerations. Zach shares insights into modern fiberglass materials, which have improved safety compared to older versions, and discusses the importance of proper cleaning and coating techniques. The conversation also touches on broader indoor air quality challenges, including the impact of tighter building envelopes, ventilation issues, and the potential health risks of prolonged exposure to indoor contaminants. Key Topics Covered: Ethical considerations in duct cleaning Assessment techniques for determining cleanability Different duct materials (metal, flex, fiberglass) and cleaning approaches Indoor air quality challenges in modern homes NADCA (National Air Duct Cleaners Association) standards Importance of technician certification and experience Ventilation and its impact on indoor air quality Proper testing and verification of cleaning results Coating techniques for fiberglass ducts Misconceptions about antimicrobial treatments Learn more about NADCA and certified professionals at https://nadca.com/. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.