Ductwork Services Explained: Sealing, Cleaning, Balancing and Design

Seal first in almost every case. Cleaning ducts that still leak fills them again with attic dust. The exception is a home fresh out of a remodel with visible drywall debris in the runs, where cleaning comes first and sealing follows so the result lasts.

Cloth-backed tape dries out and lets go in attic heat, often within a few summers. Mastic and UL-listed foil tape are made for the job and hold. Most of the leaks we find in older Phoenix homes are at joints where the original tape simply gave up.

Possibly. Sizing is a load calculation, and delivered airflow is part of it. A system that no longer loses a quarter of its air may not need the capacity the old one had. The installation guide explains how sizing is done on site, never from a web page.

Yes, in a house with a single hallway return. A closed door cuts off the return path, pressure builds in the room, and airflow to it drops. Jumper ducts or transfer grilles restore the path. It is one of the cheaper items on the return air upgrade list.

The register boots visible from inside the room are reachable. The bulk of the leakage is in the attic, at joints and plenums, and a Phoenix attic in summer is not a place we recommend anyone spend an afternoon. Have the leakage measured first so you know whether the work is worth doing at all.

Yes. The unit sits on the roof, but the ducts still drop through the attic, and the connection at the roof curb is a common leak point. Our rooftop unit page covers what is different about servicing them.

Sometimes, particularly when the equipment is being replaced anyway. A test that shows high static pressure and a return that cannot be enlarged points toward redesign. A test that shows modest leakage points toward sealing and stopping there. A whole-home comfort assessment gives you the answer with numbers attached.