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CHAPTER 5: DUCT CARE
5.1 Duct Cleaning
Properly maintained HVAC systems with regular filter changes should not require cleaning.
The "cleaning" of all air duct types has become a common practice. This section addresses only the removal of dust and debris from the inside surface of flexible ducts "cleaning" can infer additional aspects.
Prior to “ cleaning ” the duct the owner should consider duct replacement, especially if the air distribution system is 15+ years old. Replacing a duct system with improved R - Value insulation requirements and much tighter installation methods should not only provide clean ducts but also provide lower future energy costs to operate the system. If "cleaning" is preferred, its recommended to use a qualified technician that follows the procedures outlined by the National Air Duct Cleaners Association (NADCA) or another nationally recognized duct cleaning organization. The recommended “ cleaning ” method uses a rotating brush and vacuum process per NADCA. Flexible duct inner liners may be damaged by other overly aggressive contaminant removal techniques, such as high - pressure blow guns, air skipper, and air whips.
When the “ cleaning ” process is completed, any flexible duct connections that were opened must be properly resealed to maintain air tightness and duct thermal properties.
5.2 Duct Replacement
Properly installed, flexible duct should last the life of the dwelling. During this time however, the home may go through multiple HVAC unit replacements without upgrading the ducting. By ignoring the ducting, homeowners are missing a potential opportunity to improve system energy efficiency through duct sealing and R - Value improvement. Flexible duct manufacturers continuously work toward increased energy improvements offering ducts with R - Value from R4.2 to R6 to R8. Replacing older, poorly - sealed, R - 4.2 ducts with properly sealed R - 6 or R - 8 ducts can ensure the homeowner maximizes system efficiency and comfort.
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5.3 Repairing Torn or Damaged Duct
Tears to flexible duct vapor barriers can be repaired using tape listed and labeled to UL 181B. Extensive damage may require replacement of the duct. It is not recommended to wrap ducts with a new vapor barrier as this can invalidate the product listing.
If the internal core is penetrated, damaged, or torn the ducting should be replaced or spliced per Section 4.7.
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