Indoor Air Quality, Duct Repair and Duct Replacement in DeBary

• Musty smell when the system starts. Mold on the indoor coil, in the drain pan or on the blower wheel.
• Dust that comes right back. A filter that does not fit its slot, or a leaking return duct pulling attic dust and insulation fibers into the air stream.
• Hot rooms. A crushed, kinked or disconnected duct run, usually in the attic.
• High bills. Leaky supply ducts dump cooled air into a hot attic, and the system runs longer to make up the difference.
• Sticky air at a comfortable temperature. The system is cooling but not removing enough moisture.

Since January 2023, ductwork has come up in our residential job notes more often than any other subject except AC repair.

In Central Florida the indoor coil stays cold and wet for most of the year, inside a dark cabinet full of warm air. Mold settles on the coil, in the drain pan and on duct liner, and the blower carries the smell through the house. Attics make it worse: any duct that leaks or has lost its insulation sweats in the heat, drips onto the ceiling and grows mold on its outer jacket too.

Removing moisture is half of what an AC does here. A system that is too large shuts off before the coil has wrung the water out of the air. Leaving the thermostat fan on On instead of Auto blows water from the wet coil back into the house. When the equipment and settings are right and the house still feels damp, a dedicated dehumidifier may be the answer. We check equipment size, settings and ducts first, then tell you which fix fits.

A UV light mounted in the air handler shines on the coil and drain pan and keeps mold from taking hold on those wet surfaces. It treats growth inside the system; it does not clean the air in your rooms. An air purifier installed in the return captures fine particles such as pollen, smoke and pet dander as air passes through it. UV lights and purifiers have come up about 200 times in our job notes since January 2023.

MERV ratings

A filter's MERV rating tells you how small a particle it can trap, and a higher number traps more. Higher-rated filters are also denser, and on a system with small return ducts they can cut airflow enough to freeze the coil or strain the blower. We can tell you the highest rating your system handles. Thin fiberglass filters protect the equipment but do little for the air you breathe.

Changing the filter

Slide the new filter in with the arrow on the frame pointing toward the air handler, and write the date on the frame so you know when it went in. A filter that bows, has gaps at the edges or is the wrong size lets dust straight onto the coil, where it mixes with moisture and feeds mold.

Current offer: Free UV light ($299 value) with a new AC system installation. See AC replacement and installation.

Most homes here run flexible duct through the attic. It gets flattened under stored boxes or a stray foot, kinks where it bends too tightly, sags between supports, and pulls loose from the plenum or the ceiling boots. Rodents chew it, and the outer jacket tears and sweats. A disconnected supply run can blow cooled air into the attic for years before anyone links it to the warm room it was meant to serve.

We go into the attic, follow each run and walk you through what we found. Loose and torn runs are reattached or replaced, and the joints are sealed with mastic, a paste that stays flexible and outlasts tape. OUC customers in parts of Orlando and Orange County can claim this rebate:

• Duct repair or replacement: up to $100 when sealed with mastic

Amounts change, so check financing and rebates before the work starts.

Repair makes sense when a few runs are the problem and the rest is sound. Replacement makes sense when the flex duct is old and brittle, when duct board is crumbling or moldy inside, when runs were undersized from the start, or when several rooms are uncomfortable at once. The easiest time is during an AC replacement, since the air handler is already disconnected and the new ducts can be sized for the new system. New ductwork is sized to the house, sealed with mastic and insulated.

Returns get the same attention. Many homes have one central return in a hallway, so a bedroom with its door shut cannot push its air back to the system, and the room stays stuffy. A transfer grille or a jumper duct gives that air a path home without opening a new hole in the main trunk.

For keeping the coil and drain clean between visits, see AC tune-ups and maintenance plans. If the system has stopped cooling altogether, see AC repair.