A duct cleaning company can clean a duct. A licensed HVAC contractor can tell you why it got dirty, whether it matters, and what it is doing to your equipment. Those are not the same service, and the difference shows up in what ends up on your estimate.

Most homes in Georgetown have the same basic setup: a furnace or air handler in a closet or attic, a coil sitting on top of it, and two large boxes called plenums where the air enters and leaves. Flexible ducts run from there to every room. Air moves through all of it, and
anything in the path ends up in the house.

What a cleaning-only company is equipped to do

Run a brush and a vacuum through the ductwork. That genuinely helps when the problem is loose dust on metal duct, and a good one will do it carefully.

What they are not set up to do is diagnose. If the blower wheel is loaded with dirt, that is an HVAC repair. If the coil can only be reached from one side, cleaning the other side means removing it, which means handling refrigerant. If the plenum is fiberglass duct
board with growth in it, no amount of cleaning fixes it and the box has to be rebuilt. Those are licensed trade jobs. A cleaning company that runs into one has to tell you to call somebody else, or clean around it and not mention it.

What NADCA certification adds

NADCA is the National Air Duct Cleaners Association, and it publishes the industry standard for this work, called ACR. The certification our team holds is Air Systems Cleaning Specialist, earned by examination.

The standard matters because it settles the parts people argue about. All loose debris has to be physically removed rather than treated in place. Both sides of a coil have to be cleaned, not just the side you can see. Porous material with mold growing in it cannot be cleaned and has to be replaced. Vacuum equipment exhausting indoors must be HEPA filtered, including the hand vacuums used on coils and cabinets. Service openings cut into ductwork have to be sealed to a specified standard so they become permanent access rather than a patch.

Without the standard, every one of those is a judgment call made by whoever is holding the tool.

Why one company should hold both

Because the two halves describe the same system.

The measurement that tells you the most about a residential system costs ten minutes and a drill bit: static pressure, the air pressure moving through the equipment. A high reading means the system is fighting something. It does not tell you what, which is where the camera and the open cabinet come in. Interpreting that number is HVAC work. Knowing what to do about a loaded coil or a contaminated plenum is NADCA work. Doing both in one visit is how a homeowner gets an answer instead of two opinions.

It also means that when we find something, we can fix it. A rusted secondary drain pan, a missing float switch, a plenum that needs rebuilding in sheet metal — those are repairs, not cleanings, and they require a license.

What to ask whoever you call

  • Are you NADCA certified, and who on the crew holds the certification?
  • Are you a licensed HVAC contractor, and what is your license number?
  • Will you measure static pressure before and after?
  • How will you clean both sides of the coil?
  • What do you do if you find mold on fiberglass duct board?

The last one is the most revealing. The correct answer is that it has to be removed and replaced, because no sanitizer is approved for porous surfaces inside an air system.

Miller Climate Control is NADCA certified and a licensed Texas HVAC contractor, TACLA24427C. We have been in Georgetown since day one.