What is the minimum clearance to combustibles for a duct carrying heat from a furnace?

In HVAC systems, ensuring safety and efficiency involves adherence to specific clearances from combustibles when installing ducts that carry heat from a furnace. The correct approach is to follow manufacturer specifications because these guidelines are designed based on the specific materials and designs of the HVAC equipment being used.

Manufacturer specifications take into account various factors, including the materials used for the ductwork, the type of insulation, the furnace model, and the heat output. These considerations allow for a tailored and safe installation that mitigates the risk of fire hazards from heat transfer to surrounding materials.

While general values like 3 inches, 6 inches, or 12 inches might be prevalent in some codes, they may not apply universally and can vary significantly based on the manufacturer's guidelines. Therefore, always consulting the manufacturer's specifications ensures compliance with safety standards and optimal operation of the heating system.