Cleaning removes lint. Repair fixes the reason lint accumulated. Confusing the two means paying for cleaning repeatedly on a duct that will always block. Here is how to tell them apart.
What Cleaning Fixes
Lint. That is the whole list. A correctly built duct of the right material and reasonable length, cleaned properly, will run for twelve to twenty-four months before needing attention again depending on usage and climate. If your property’s vents behave that way, cleaning is all you need.
What Cleaning Does Not Fix
Crushed or kinked duct sections. A duct squashed behind a dryer, or crushed where it passes through framing, restricts airflow permanently. Cleaning it changes nothing. It needs replacing.
Disconnected runs. A duct that has come apart inside a wall or ceiling is venting hot, moist, lint-laden air into the building structure. Cleaning the accessible sections does not reconnect it — and this is the most serious deficiency we find, because it deposits fuel into concealed spaces and moisture into insulation while the resident reports no problem at all.
Foil or vinyl flex duct in concealed spaces. A code violation in most jurisdictions, and functionally a lint trap: every corrugation catches fibre. Cleaning removes what the brush can reach; the valleys refill within months. It needs replacing with rigid smooth-wall metal.
Screws protruding into the airstream. Every joint fastened with screws that penetrate the duct interior is a permanent snag. Cleaning removes the lint; the snags remain.
Screened termination caps. A screen at the termination catches lint on the inside and builds a mat. It will do so again immediately. The cap needs replacing with a proper dryer vent cap with a free-swinging damper.
Failed backdraft dampers. A damper that will not open restricts airflow; one that will not close admits pests. Neither is a cleaning problem.
Excessive developed length. A run longer than code permits, with too many elbows, cannot move sufficient air regardless of how clean it is. It needs redesign, rerouting or a listed booster fan.
How You Find Out Which You Have
Airflow verification after cleaning. A unit that still shows restricted airflow once the duct is clean has a physical problem, not a lint problem. That is the diagnostic, and it is why airflow measurement at every unit is not an optional extra — it is what separates the two categories.
What This Means for Budgeting
Budget cleaning as an annual or biennial operating line. Budget a remediation contingency alongside the first-ever clean at a property — typically 10-20% of the cleaning cost — because the first clean is when the physical deficiencies get counted for the first time.
A property that cleans every year and never remediates its foil flex duct is buying the same problem annually and calling it maintenance.
What We Deliver
Cleaning, airflow verification at every unit, and a photographed, located deficiency log distinguishing what we cleaned from what needs fixing. Your maintenance team gets a punch list; your budget gets a number.