John Ellis is widely recognized as one of the leading experts in building science, earning tremendous respect from his industry peers for his deep technical knowledge and systemic approach to the indoor environment. John views a building not just as a collection of parts, but as a complex, interconnected system. With more than 40 years of hands-on experience in the HVAC industry, he focuses on diagnosing complex indoor air quality (IAQ) issues and providing field coaching to professionals during the discovery, design, and implementation of high-performance building solutions. His approach perfectly bridges the gap between mechanical engineering and building science, ensuring that structures function safely, efficiently, and healthily.  

John’s deep understanding of structural dynamics and airflow comes from a rich, varied background in the trades, having spent time in prominent industry unions for sheetmetal workers, pipefitters, and operating engineers. Over his career, he has managed large-scale mechanical projects for highly demanding environments, including hospitals, hotels, water treatment plants, and correctional facilities. Recognizing that structural performance directly impacts occupant health, John dedicated a year to a pilot study for the South Coast Air Quality Management District, where he installed and tested High-Performance Filtration systems to improve ambient air quality in schools.

Before shifting his focus exclusively to consulting and training, John operated a performance-based contracting firm specializing in the intersection of mechanical design, forensics, and hygrothermal performance. By applying rigorous diagnostic metrics, he engineered optimized, health-first indoor environments tailored for clients with severe respiratory conditions and compromised immune systems.