A hood moves only as much air as its duct lets through. A long run, many elbows, or a narrow pipe adds resistance, and no blower can fully overcome a poor path.
Signs the duct is limiting airflow
- The fan sounds strong but little air reaches the exterior cap.
- Smoke clears slowly even on high.
- Grease or moisture collects in the duct or at the hood.
- Performance was never good, even when the hood was new.
Why it happens
Every elbow and every foot of pipe adds friction, and a duct that shrinks in diameter chokes the flow. In older Houston homes, a duct routed through an attic can also collect heat and condensation.
What can be fixed
A damper stuck partly closed, a clogged exterior cap, or a loose joint can be corrected. A badly routed duct needs a contractor, and an honest estimate will say so. We can check the hood side, then tell you what remains, so you know which part of the airflow problem sits with the hood and which sits with the house.
What about exterior caps
The cap outside the house can fill with lint, bird nests, or leaves, and it takes a few minutes to check from the ground in many homes. Seeing the flap lift when the fan starts tells you the damper is moving. A flap that stays shut under a running fan means the air has nowhere to go.
If you find a crushed or kinked section in the flexible duct, that alone can account for a big loss in flow. Straightening it is a better first step than replacing the blower.
We check the blower, damper, and cap and tell you what is the hood and what is the house. Read about range hood repair or the areas we cover.