Ductwork, airflow, and humidity in Tampa Bay

Many of the "my AC is not big enough" calls around the bay turn out to be duct calls. Ducts in a vented attic that hits 130 °F in July leak conditioned air out and pull attic air in; a house with one return in the hallway starves the bedrooms; a system oversized for the house cools the air and leaves the humidity. The fix is measured on the air side, not by the size of the condenser.

Call or send the form and get connected with an independent local air-conditioning contractor who serves your part of Hillsborough or Pinellas and does duct work, not just change-outs. Ask for the tests before the quote.

What the housing does to the air side

• Retrofit central air in 1920s–50s houses (Hyde Park, Seminole Heights, Kenwood, Old Northeast): ducts added where they fit, one small return, an air handler in a closet. The rooms at the end of the run never cool.
• 1970s–90s block houses (Brandon, Carrollwood, Pinellas Park, Largo): shallow attics, flex duct that has sagged and kinked, connections that were taped twice. Two or three condensers have been replaced on the same ducts.
• 1990s–2010s subdivisions (New Tampa, Riverview): ducts in a vented attic, a second floor that runs ten degrees warmer, a single zone doing two jobs.
• Flat-roof additions and Florida rooms (St. Petersburg, Largo): a duct that was never sized for the room, or none at all.

Humidity is the Florida problem

A July dew point of 73 °F means the air carries water all day. A properly sized system runs long enough to wring it out; an oversized one hits the setpoint in ten minutes and leaves the house at 75 °F and damp, which is why a house can feel worse after a "bigger" system. The remedies are sizing from a load calculation, longer run times, sealed ducts so attic air stops coming in, and, where the house still cannot keep up, a whole-house dehumidifier on the return. Florida's energy code sizes equipment by Manual J and Manual S for exactly this reason.

What the visit should include

• Static pressure at the air handler and airflow at the registers; a duct leakage test if the ducts are suspect (the energy code requires one on new duct systems).
• A look in the attic: disconnected runs, crushed flex, missing insulation, returns pulling from the attic.
• A written scope: seal, repair, add returns, or replace the ducts; the permit if the ducts are replaced (a mechanical permit, same as a change-out).
• Indoor air quality without the sales pitch: a better filter and a sealed return do more than most add-ons; UV lights and "air purifiers" are an option, not a fix for leaking ducts.