Duct Replacement and Sealing in Greater Jacksonville

In a typical house, about 20 to 30 percent of the air that moves through the duct system is lost to leaks, holes, and poorly connected ducts (ENERGY STAR, Duct Sealing). In a Florida attic that bakes all summer, the loss is often worse. Fouraker Mechanical tests, repairs, seals, and replaces residential duct systems across Greater Jacksonville and Nassau County so your equipment can do its job and every room reaches the temperature on the thermostat.

What We Offer

Signs your ductwork is the problem

A lot of calls that start as 'my AC is not keeping up' end with a duct repair instead of an equipment repair.

• Rooms that never reach the set temperature, especially at the end of long duct runs
• High utility bills despite a newer, properly working HVAC system
• Unusual dust levels, or dust blowing from the registers
• Musty odors in certain rooms, a sign of leaks pulling attic or crawl space air into the system
• Weak airflow at some registers and strong airflow at others
• Ducts that are original to a home built before the mid-1990s

A static pressure test and a visual inspection tell us exactly what is happening inside the system. We do both before recommending anything.

Why Florida attics are so hard on ductwork

Most Greater Jacksonville homes run their ducts through an attic that reaches well over 120 degrees on a summer afternoon.

• Heat gain: Cooled air travels through a hot attic and arrives warmer than it left the air handler, even in a sealed duct. Insulation value matters.
• Tape failure: The adhesive on standard duct tape softens and lets go in attic heat. Joints that were taped at construction are often open within a few years.
• Flex duct sag and crush: Flex runs that were not supported properly sag, kink, and restrict airflow. Stored items in the attic crush them.
• Humidity and condensation: Leaky return ducts pull humid attic air into the system, which raises indoor humidity and feeds mold on the coil.

How we evaluate a duct system

We do not guess at ductwork. Here is the process.

• Static pressure test: Measures how hard the blower is working against the ducts. High readings mean restriction, undersizing, or a dirty coil.
• Visual attic inspection: Disconnected runs, crushed flex, open joints, missing insulation, and returns pulling from the attic.
• Airflow at the registers: Confirms which rooms are starved and whether the trunk and branch sizing match the equipment.
• Written report: What we found, what it is costing you, and your options from targeted sealing to full replacement, each priced.

Seal, repair, or replace

Not every duct problem needs a new system. We match the fix to what the test shows.

• Seal: Joints and connections leak but the layout and sizing are fine. Mastic and proper collars close the gaps.
• Repair: A few runs are crushed, disconnected, or torn. We replace those sections and seal the rest.
• Replace: The system is undersized for the equipment, the duct board or flex is deteriorating, or the layout leaves rooms without supply. A redesigned system fixes comfort for good.
• Zone: Two-story homes and large single-story layouts often benefit from zoning dampers so upstairs and downstairs get the airflow each actually needs.

Financing through FTL Finance is available for full duct replacements and for duct work bundled with a new system.

Ductwork and your indoor air

Leaky return ducts do more than waste cooling. They pull unfiltered attic and crawl space air into the system, bypassing the filter entirely.

That is why homes with duct problems often show dust, musty odors, and humidity that the AC cannot seem to control. Sealing the return side is one of the most effective indoor air quality improvements available, and it costs less than most equipment add-ons. Our indoor air quality guide covers the rest of the picture.