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Costs & Financing

Ductwork Replacement: What Moves the Price

Ductwork replacement is priced by access, length and layout, material and insulation level, and how many supply and return corrections the design needs. It is the least glamorous purchase in comfort — and often the one that changes a home the most.

Access rules everything

The same duct system costs very different amounts in a walkable attic versus a tight crawl space. Labor hours live and die on access.

Charleston's raised homes put much of the housing stock's ductwork in humid crawl spaces — where age, moisture, and pests do their work and access is honest labor.

Design corrections, not just copies

Replacement is the moment to fix the original sins: undersized trunks, rooms with no return path, and runs that were always too long. Copying bad ductwork in new material wastes the opportunity.

Balanced returns and right-sized runs are why a duct replacement can transform rooms a thermostat war never fixed.

Sealing and insulation levels

Sealed, well-insulated ducts in unconditioned space stop the leak-your-cooling-into-the-crawl-space tax every older system pays. Material and insulation tier move price and repay in operating cost.

In our humidity, sealed ducts also resist the condensation that soaks insulation and breeds the musty-vent smell.

Repair or replace the ducts

Localized damage repairs well. Systemic leakage, crushed runs, ancient duct board, or pest history argue for replacement — patching a failing network yearly costs more than owning a sound one.

We assess honestly and show you what we find, photos included.

Written and reviewed by the Holy City Heating & Air team

Licensed South Carolina mechanical contractor (License #M113404, verifiable at LLR Online) — local technicians serving Charleston and the Lowcountry since 2015. See our certifications & awards and our story.

Last updated July 4, 2026 · Guides are grounded in what our technicians see in Charleston homes; official sources are linked above where a claim depends on them. Every recommendation still needs an in-person diagnosis.

Frequently asked questions


How do I know my ducts leak?

Rooms that never condition, dusty air, whistle sounds, and cooling bills out of proportion to equipment age all point at ducts. A proper assessment measures rather than guesses.

Should ducts be replaced with the system?

If the ducts are near end of life, doing both at once is cheaper than twice-mobilized labor and lets the new equipment be sized to the corrected duct design.

Do sealed ducts really matter for humidity?

Yes — leaky returns pull humid crawl-space air straight into the system. Sealing them is one of the quieter humidity wins available in a Lowcountry home.

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