HVAC or heating ventilation and air conditioning is a licensed sub specialty. We use HVAC sub contractors who ensure high quality while mitigating expenses. The role of the GC is to ensure that HVAC work is coordinated with all the other sub contractors. Inspections need to be coordinated at the appropriate times. For new construction 2 inspections including the equivalent of a pressure test of the ducts will be required. On existing construction only one inspection is required. It should be noted that you may need to get your framer involved at this point. New code requires a clear walking path exist to any unit in the attic. Also an insulation inspection will be needed at some point.