Should You Clean or Replace Your Air Ducts?
Raleigh homeowners ask about this regularly. One r/raleigh thread asks for the standard price range to replace ductwork; in an r/triangle thread about duct cleaning, a commenter's advice is simply: "If you're truly worried about your duct work just replace it." Both are reasonable, but cleaning and replacement solve different problems — and most homes need neither, or something else entirely. We clean ducts; we don't install them. So this is the honest version of the answer.
The short version: Clean ducts that are intact but dirty. Replace ducts that are wet, moldy and insulated, or physically damaged. Seal ducts that leak. And whatever you do, the EPA's first rule applies: "Prior to any cleaning, retrofitting, or replacing of your ducts, the cause or causes must be corrected or else the problem will likely recur."
When cleaning is the right call
The EPA recommends cleaning when ducts are "visibly contaminated with substantial mold growth, pests or vermin, or are clogged with substantial deposits of dust or debris." In practice that also covers homes after a renovation, when drywall dust and sawdust end up in the ducts. If the ducts themselves are sound, cleaning removes what's inside them, and replacing them would be paying for new ducts to solve a dirt problem. Our guide on whether duct cleaning is worth it goes through those cases.
When replacement is the right call
- Wet or moldy insulated duct. The EPA is direct about it: if insulated ducts get wet or moldy, the insulation "cannot be effectively cleaned and should be removed and replaced." That includes fiberglass duct board and ducts lined with fiberglass.
- Damaged flex duct. Crushed, torn or collapsed runs restrict airflow, and cleaning won't reopen them. The EPA also notes that for flex duct, "it can be more economical to simply replace accessible flex duct." More on that in our flex duct guide.
- Disconnected or chewed runs. A section that has come apart in the attic, or one rodents have been through, is a repair job, not a cleaning job.
- A new HVAC system. When the equipment is being replaced anyway, it's the natural time to ask the installer whether the existing ducts suit it.
The problem many homes actually have: leaks
Rooms that never get comfortable, or bills that seem high, often point to neither dirt nor age. According to ENERGY STAR, "in a typical house, about 20 to 30 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts." It lists the signs: high summer and winter utility bills, rooms that are hard to heat and cool, stuffy rooms, and ducts that run through an attic, crawlspace or garage — which describes a lot of Triangle homes.
The fix for leaks is sealing: ENERGY STAR recommends mastic sealant or metal tape on the joints, insulating the ducts you can reach, and checking where registers meet floors, walls and ceilings. It also says to never use duct tape, because it doesn't last. Sealing doesn't require new ducts, and cleaning won't close a leak.
A caution for older homes
In older Triangle homes — mid-century ranches in Garner, bungalows in Durham — old ducts sometimes carry wrap or tape that nobody has identified. The EPA's asbestos guidance is that you generally can't tell whether a material contains asbestos by looking at it, so "if in doubt, treat the material as if it contains asbestos and leave it alone." If old ductwork is coming out, get unknown materials checked first by an accredited asbestos professional.
Who does each job in North Carolina
Cleaning is what a duct cleaning company like ours does. Replacing or altering ductwork is heating contractor work: North Carolina's licensing law (G.S. 87-21) covers residential forced-air systems that use "an air distribution system of ducts." You can check a contractor's license with the NC State Board of Examiners of Plumbing, Heating, and Fire Sprinkler Contractors. Replacement is quoted job by job, so get written quotes from more than one licensed contractor.
How we handle it
Every job starts with an inspection and photos. If we find a crushed run, a disconnected section, or wet or moldy insulated duct, we show you, we tell you cleaning won't fix it, and you keep the photos to hand to a heating contractor. If the ducts are sound but dirty, cleaning starts at $300 for a standard home up to 2,000 sq ft and $450 for a larger one.
Not Sure Which One You Need?
We inspect and photograph your ducts before any work. If cleaning won't fix what we find, we'll tell you before you pay for it.
See our prices →Frequently Asked Questions
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