Ductwork Installation & Repair Cost in Philadelphia

Based on 23 ductwork jobs completed by McCorry Comfort, January 2024–February 2026

Ductwork is one of the most misunderstood cost areas in HVAC. The range is enormous — from a $150 repair to a $124,000 commercial installation. Most homeowners are dealing with something in between, but knowing where you fall on that spectrum before calling anyone is useful.

Our data from 23 ductwork jobs: average of $7,100, median of $1,388. The average is heavily pulled up by the Philadelphia commercial job that topped out at $124,919. Strip that out and the numbers look very different for residential work.

Ductwork Cost Summary

Metric	Cost
Average	$7,100
Median	$1,388
10th percentile	$190
25th percentile	$720
75th percentile	$2,675
90th percentile	$4,921
Minimum	$150
Maximum	$124,919

Cost by Location

Location	Jobs	Average	Range
Philadelphia	7	$19,696	$720–$124,919
King of Prussia	2	$1,846	$1,192–$2,500
Horsham	2	$1,607	$1,550–$1,664
Ambler	1	$2,675	—
Laurel Springs	1	$5,100	—
Glenside	2	$975	$150–$1,800
Rose Valley	1	$1,020	—

Philadelphia's average is distorted by the large commercial job. The suburban residential jobs (King of Prussia, Horsham, Ambler, Glenside) are much more representative of what homeowners typically spend: $1,000–$3,000 for repairs and partial replacements.

Types of Ductwork Jobs and What They Cost

Minor Repairs — $150–$700

Reconnecting a separated flexible duct section, sealing a leaky joint, replacing a damaged register or diffuser, or patching a crushed flex duct run. These are quick jobs — usually identified during maintenance or when a specific room isn't getting conditioned air.

Section Replacement — $500–$2,000

Replacing a specific run of ductwork — typically flex duct that's been damaged, kinked, or has failed insulation. Common in attics and crawlspaces. Price depends on length, accessibility, and whether it's rigid metal or flex.

Duct Sealing and Insulation — $800–$3,000

Systematic mastic sealing of leaky joints throughout an accessible duct system, often combined with re-insulating uninsulated or poorly insulated duct runs in unconditioned spaces. This has a clear ROI — energy savings compound over time.

Partial System Redesign — $2,000–$6,000

Redesigning or replacing a portion of the supply or return system — often done when adding rooms, reconfiguring space, or fixing an imbalanced system that's never performed well. Requires sheet metal work, new register locations, and sometimes structural coordination.

Full Duct System Installation — $8,000–$30,000+

Installing a complete duct system in a home that either never had one or had a system that was removed. This involves designing the system (Manual D calculation for proper sizing), fabricating trunk lines and branches, installing registers and returns, and balancing the system. It's a multi-day job and typically requires opening finished surfaces.

Flex Duct vs. Sheet Metal: What's the Difference?

Most residential systems use a combination — sheet metal for the main trunk lines and flex duct for the branch runs to each room. Here's the practical breakdown:

Sheet Metal (Rigid Duct)

• More expensive to fabricate and install
• Lower airflow resistance — better for long runs
• Lasts indefinitely if properly sealed and insulated
• Easier to clean

Flexible Duct

• Less expensive, faster to install
• More flexible for routing around obstructions
• Degrades over time (typical lifespan 15–25 years)
• Prone to kinking if not properly supported, which drastically reduces airflow
• Inner liner can separate from outer insulation in older flex duct

In Philadelphia attics and crawlspaces — where temperatures swing dramatically — flex duct tends to degrade faster than in conditioned spaces. If your flex duct is over 20 years old, it's worth having the condition assessed.

Philadelphia Specific: Homes Without Ductwork

A large portion of older Philadelphia rowhomes and twins were built with hot-water or steam heat and no ductwork. When these homeowners want to add central AC (or want to convert to a heat pump), they face a choice:

Option 1: Install full ductwork

Expensive ($10,000–$25,000+ typically), disruptive, and requires significant finish work to restore the walls and ceilings. Makes sense if you have a larger home, prefer a conventional HVAC setup, and plan to stay long-term.

Option 2: Mini-split system

No ductwork required. Individual indoor heads in each zone, connected to an outdoor unit. Typically runs $3,000–$10,000 for a 2–3 zone residential installation. Less disruptive, more control by zone, and lower installation cost. The trade-off is visible indoor heads on the wall or ceiling.

We'll walk you through both options honestly and tell you what makes sense for your specific house. The right answer isn't the same for every property.

Getting an Accurate Ductwork Quote

We need to see your current system to quote ductwork work accurately. That means accessing the attic, basement, and any crawlspaces. We'll photograph what we find, document the issues, and tell you what we'd recommend — repair, partial replacement, or a redesign if the system is fundamentally flawed.

Ductwork quotes over the phone are guesses. We don't do guesses.

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Ductwork Questions or Problems?

Whether it's a repair, a sealing job, or a full replacement, we'll come out and tell you what you're actually dealing with.

McCorry Comfort
📞 (215) 399-2056
🌐 mccorrycomfort.com
Serving Philadelphia, King of Prussia, Horsham, Ambler, Glenside, and surrounding suburbs