If you have looked into your air ducts at all, you have probably seen two services that sound almost the same: duct cleaning and duct sealing. They are not the same job, they do not fix the same problem, and paying for the wrong one is a common way to spend money without feeling any difference in the house.
Here is how to tell which one your home needs.
What duct cleaning does
Duct cleaning removes what has built up inside the air ducts over the years: dust, pet hair, construction debris, and in a humid climate like ours, sometimes mold growth. A proper cleaning uses mechanical agitation and strong vacuum collection on both the supply and return runs, followed by a fresh filter.
Cleaning is about air quality. It does not make the system cool better in any meaningful way, and it will not lower your FPL bill. If someone promises big energy savings from cleaning alone, be skeptical.
What duct sealing does
Duct sealing closes the gaps where conditioned air escapes before it reaches a room. In most South Florida homes the air ducts run through the attic, where summer temperatures regularly reach 120 to 140 degrees. Every loose joint, torn section of flex duct, or separated connection leaks cold air into that attic and pulls hot, dusty attic air into the system.
Sealing is about comfort and cost. Industry studies commonly find that a typical home loses 20 to 30 percent of its conditioned air through leaky ducts. Seal those leaks with mastic and rated tape and more of the air you are paying to cool arrives where you want it.
Signs you need cleaning
- Visible dust blowing from the vents when the system starts.
- A musty smell that shows up when the AC kicks on.
- Recent renovation, drywall work, or flooring work in the home.
- Visible mold around vents or inside the air handler.
- Pets, smokers, or allergy concerns in the household, and it has been more than a few years.
Signs you need sealing
- One or two rooms that never get as cool as the rest of the house.
- An AC that runs almost constantly on hot afternoons.
- Electric bills that keep climbing even though your habits have not changed.
- Dust that comes back quickly after you clean, which often means the system is pulling attic air in through a leak.
- Weak airflow at vents that are far from the air handler.
Why the order matters
If your air ducts leak, cleaning them first is partly wasted effort. A leaky return keeps pulling attic dust and insulation fibers into the system, so the ducts get dirty again fast. In most cases the right order is to find and seal the leaks first, then clean if the inside of the ducts still needs it.
Sometimes neither is the answer. Ducts that are crushed, badly undersized, or falling apart with age need repair or replacement, and no amount of cleaning or sealing will change that.
How to know for sure
You do not have to guess. A static pressure and airflow test takes about 15 minutes and shows whether the duct system is leaking or restricted. A visual inspection of the attic runs, with photos, shows the condition of the ducts themselves. Ask whoever inspects your system to show you what they found before they recommend anything.
The bottom line
Cleaning is for the air you breathe. Sealing is for comfort and the monthly bill. Many homes need one and not the other, and an honest inspection will tell you which.
A Kool Saver is a state licensed Florida mechanical contractor serving Miami Dade, Broward, and Palm Beach counties. We inspect air ducts for free and quote only what needs work. Request a free quote or learn more about our air duct services.