Almost always air distribution rather than equipment. The run serving that room may be undersized, crushed, leaking, or too long for the airflow it needs to deliver, or the building may lack the return path to pull air back out. Measuring airflow room by room and static pressure at the air handler identifies which, and balancing or resizing corrects it.

Static pressure is the resistance the duct system creates against the blower — essentially how hard the equipment has to push to move air. High static pressure means the system is fighting its own ductwork, which reduces airflow, hurts humidity removal, and shortens blower and compressor life. It is a measured number, not a judgment call, which is why we test rather than estimate.

In Florida, more than in most climates. Conditioned air escaping into a hot attic is money spent cooling a space you do not occupy, and on the return side leaks pull hot, humid attic air into the system, which raises indoor humidity and adds runtime. Sealing supply and return connections is usually the highest-return duct work available.

If the layout is fundamentally right and the problem is leakage, damage, or insulation, repair and sealing restore performance at far lower cost. If runs are undersized, poorly routed, or the return is inadequate, sealing a bad design just seals a bad design — that needs resizing or redesign. The evaluation tells you which situation you have.

Because the ductwork was the problem. New equipment behind restricted or leaking duct delivers the same uneven temperatures and the same humidity, and a system correctly sized for the building can still be strangled by runs sized for a different one. This is the most common reason a replacement disappoints.

Often, yes, in newer construction. Tightly sealed buildings are efficient but have no controlled path for fresh air, so indoor air goes stale and moisture accumulates with nowhere to go. Mechanical ventilation introduces outdoor air and exhausts stale air deliberately, rather than leaving it to whatever leaks the building happens to have.

Sometimes, and sometimes it is the wrong tool. Zoning is right when different areas genuinely need different temperatures — a second storey, a west-facing room, a converted space. It is not a substitute for fixing leakage or undersized return, because zoning a system with a duct fault just distributes the fault differently. We check airflow first, then recommend zoning if it is warranted.