Certified HVAC technicians have a big job. They must keep up with all the new innovations in the heating and cooling industry, and know makes and models and how they work. They need to be experts in electronics, design and mechanics. Look for service technicians certified by the North American Technician Excellence, or NATE Inc. NATE is an industry leader in testing and certification. The EPA is among organizations that urge consumers to use technicians certified by NATE to ensure reliability.