The HVAC system of a building works hard to keep occupants cool in the summer and warm in the winter. Insulation works in tandem with the HVAC system, slowing down heat transfer from the outside of the building to within. Without insulation, the cost of heating or cooling a home would skyrocket. Air leakage in ductwork can impact the efficiency of a system, especially in regard to insulated (or uninsulated) ductwork. For those involved with insulation, some best practices can help make sure that both the HVAC system and insulation work in harmony.