Clearance to combustibles refers to the minimum safe distance required between a heating appliance and any flammable materials like wood, drywall, or insulation. This distance is strictly regulated by local building codes and manufacturer specifications to prevent the risk of fire during operation. For Mobile Home Gas Furnaces, these clearances are often very tight, requiring specialized zero-clearance cabinets. If you are installing Ducted heating, the flue pipe and the furnace body must have adequate air space to dissipate heat. Failing to respect these distances can lead to heat damage to the home's structure or even a catastrophic fire. Always refer to the installation manual of your ACIq unit to verify the specific inches of clearance needed on the front, back, and sides. Proper spacing also ensures that technicians have enough room to perform future maintenance safely. It is one of the most important safety standards in the entire HVAC industry.