Two of the most common residential systems are the perimeter duct system and the extended round system.

Using our interactive duct system maps below, you can see what parts are used where, and link to our online product catalog to see product sizes and specifications.

EXTENDED ROUND SYSTEM
Round duct systems are used where cooling is the predominant requirement and heating is secondary. These systems are found in the southern half of the United States and the Pacific Northwest.


PERIMETER SYSTEM
Perimeter duct systems represent the standard for systems where both heating and cooling are required in significant amounts. This would include the northern half of the United States.