The Garner Underground, Inc. (GUI) is a research and development company, specializing in HVAC airflow measurement, indoor air quality sensing, and demand control ventilation. Our solutions help HVAC system designers meet ASHRAE compliance standards, while improving the indoor environment. Our products, through our sister companies of Ebtron and Greentrol, can be found installed in small commercial spaces, healthcare facilities, clean rooms, to large industrial/commercial complexes spanning the globe.