Building Permit Glossary
Combustion Air
The air supply needed for fuel-burning equipment to operate safely and vent combustion products.
HVACSafety
Applies to
Furnace replacement · Mechanical · Water heaters
Project example
Replacing a furnace in a tight utility room may require a documented combustion-air path or a different equipment configuration.
Also called
combustion ventilationmakeup air
Where this term shows up in permit work and how it affects the project
It affects equipment selection, venting design, and inspection approval. Treating a replacement as a simple swap can create unsafe or unapprovable work.
If this term appears in a form, plan comment, or local ordinance, start with the building permit guide, compare it against the zoning permit guide, then use the permit guide directory to find the right local path.