Fire risk is the headline, and it is real. But it is not the only thing happening, and the other four are what usually convince people to deal with it.
1. Fire risk
Lint is highly combustible and a restricted duct traps heat. This is the reason dryer exhaust maintenance is written into fire codes for multi-family buildings.
2. Energy cost, every single load
A restricted dryer runs longer to achieve the same result. Across a year of laundry that is a measurable number on your bill, and it is being paid continuously rather than once.
3. Appliance life
Dryers are designed to exhaust freely. Running against restriction means higher internal temperatures and longer cycles, which shortens the life of heating elements and controls.
4. Indoor humidity
A dryer exhausts a lot of moisture. If the duct is restricted or disconnected in a wall or attic, that moisture is going into the building instead of outside. In Florida that is the last place you want additional humidity load.
5. Carbon monoxide, for gas dryers
A gas dryer with a blocked exhaust can back-draft combustion products into the home. This is the most serious item on the list after fire, and it is the reason a gas dryer with a suspected blockage should not simply be run harder.
What to watch for
Two cycles where one used to do, a hot laundry room, a hot dryer cabinet, damp clothes with a scorched smell, or a damper that does not open. Any of those is worth acting on.
