EP281 Building a Diagnostic-First HVAC Company with Derek Aarstad

Quotes from the episode:    "When your HVAC system is performing at 100%, but the home isn't, the problem isn't the equipment anymore."    "Our job is to be investigators first and installers second."    "Homeowners don't just need to know their HVAC system. They need to know their home."    "If you think I'm doing too much testing, I'd argue you're probably not doing enough."    Many HVAC contractors say they focus on comfort, but Derek Aarstad has built his entire business around proving where comfort problems actually originate. As the owner of DNA Heating & Cooling in Richmond, Virginia, Derek approaches every home as an investigator, using airflow measurements, static pressure, duct leakage testing, blower door testing, thermal imaging, and building science principles before recommending solutions.     In this conversation, Bill and Derek discuss why replacing equipment often fails to solve comfort complaints, how educating homeowners builds trust, and why standardized processes have been essential to growing a successful high-performance HVAC company. Derek also shares lessons learned from hiring technicians, the value of documenting every step of the customer experience, and how organizations like NCI have influenced his approach to technical excellence and continuous learning.     Whether you're an HVAC contractor, home performance professional, or simply interested in how buildings really work, this episode offers practical insights into diagnostics, customer communication, and building a business that stands out by solving problems instead of simply replacing equipment.    LinkedIn: https://www.linkedin.com/in/derek-aarstad-91a328247/   Website: https://dnarva.com/    NCI: https://www.nationalcomfortinstitute.com/    NCI Summit: https://www.gotosummit.com/      This episode was recorded in July 2026.