Reliability. Professionalism. Depth of knowledge. These and more are all characteristics you want to see in any HVAC professional working at your facility. Local reputation will tell you a lot about how a company operates, but there are also other methods you can use to get a good idea of how an HVAC business conducts itself. Professional certifications can tell you whether a company and its technicians are willing to take the extra steps to prove their abilities. One of the best known of these is NATE certification.