Ductwork, airflow, and air quality in Miami-Dade

Half the "my AC is not cooling" calls in older Miami neighborhoods are not about the AC at all. They are about ducts in a 130° attic leaking a third of the cold air before it reaches the room, returns too small to feed the system, and humidity the equipment cannot keep up with. Replacing the unit does not fix any of that.

Call dispatch or send the form; an independent local AC contractor who does duct and airflow work contacts you to set the visit.

Signs the ducts are the problem

• One or two rooms never cool while the rest of the house is fine, especially rooms at the end of the run or over the garage.
• Ducts sweating and dripping through ceilings in summer: uninsulated or torn duct in a humid attic.
• Dust that returns days after cleaning, and musty smells when the system starts.
• A system that runs all day, with power bills to match, on a house it should handle easily.
• Air handler closets with no return grille, or a return so small the door has to stay open.

What the work looks like

A contractor tests static pressure and looks at the ducts themselves: crushed flex, disconnected joints, original galvanized trunk lines with open seams, returns and supplies sized for a smaller system than the one installed. Fixes range from sealing and re-insulating what is there to re-running the flex, adding a return, or replacing the trunk lines. In converted homes in Hialeah and Westchester, the fix is often a second return and a proper plenum.

Humidity and air quality

Miami's problem is moisture more than heat. Options a contractor may raise: a whole-house dehumidifier tied into the air handler, UV lights at the coil to keep it clean, better filtration, and, on replacements, variable-speed equipment that runs longer at low speed and pulls more water out of the air. Which of these makes sense depends on the house and the system; the contractor should explain why before quoting one.