Ductwork Replacement Cost by Home Size

Cost by Home Size Overview

Home size directly determines how much ductwork your HVAC system needs. A 1,000-square-foot ranch might have 80 to 120 linear feet of ductwork, while a 3,000-square-foot two-story home can have 250 to 350 linear feet or more. At current pricing of $25 to $55 per linear foot installed, this size difference translates to thousands of dollars in project cost variation.

A typical 1,000 to 1,200 square foot home requires $1,400 to $2,500 for full ductwork replacement. These homes usually have simpler layouts with shorter duct runs and fewer supply registers, which keeps both material and labor costs down. Most small homes can be completed in one to two days by a two-person crew.

Mid-size homes between 1,500 and 2,000 square feet cost $2,500 to $4,000 for complete replacement. This is where most homeowners fall, and the wide range reflects the significant impact that home layout and duct accessibility have on the final price. A single-story ranch with exposed basement ducts costs considerably less than a two-story colonial where ducts run through enclosed walls and above finished ceilings.

Larger homes from 2,500 to 3,500 square feet typically cost $4,000 to $5,600 or more. These homes often have multiple HVAC zones, longer trunk lines, more branch runs, and complex routing requirements. Multi-story homes in this size range often cost toward the upper end because ducts must run vertically between floors, which requires more fittings, transitions, and labor.

Homes over 3,500 square feet can exceed $6,000 to $8,000 for full replacement, especially if the home has three or more HVAC zones, cathedral ceilings that create long vertical runs, or ducting that passes through multiple types of spaces including conditioned areas, unconditioned attics, and crawl spaces.

Material Costs by Duct Type

The material you choose for your replacement ductwork affects both the initial cost and the long-term value. Three main types dominate residential installations.

Galvanized sheet metal costs $10 to $15 per linear foot for materials and is the most durable option with a lifespan of 25 to 30 years. The smooth interior provides excellent airflow with minimal friction loss, which helps your HVAC system operate at peak efficiency. Sheet metal is the preferred choice for main trunk lines and in applications where ducts are exposed and visible, such as unfinished basements. The higher material cost is offset by lower lifetime costs since you are unlikely to replace metal ducts more than once in a home's lifetime.

Standard flexible duct costs $4 to $8 per linear foot and is the most affordable option. It consists of a wire coil wrapped in a plastic or foil sleeve, making it lightweight and easy to route around obstacles. The ribbed interior creates more airflow resistance than metal, which can reduce HVAC efficiency by 5 to 15 percent on longer runs. Flex duct lasts 10 to 15 years under normal conditions, making it the shorter-lived option. It is best suited for short branch runs connecting trunk lines to individual room registers.

Insulated flexible duct costs $7 to $12 per linear foot and wraps the standard flex duct in fiberglass insulation with a vapor barrier. This is the most common choice in new installations because it combines the routing flexibility of standard flex with thermal performance that reduces energy loss in unconditioned spaces like attics and crawl spaces. For ducts running through unconditioned spaces, insulated flex is essentially mandatory, since uninsulated ducts in a hot attic can lose 20 to 30 percent of their cooling capacity before the air ever reaches the room.

Labor Costs and What Affects Them

Labor typically accounts for 50 to 60 percent of a ductwork replacement project. HVAC contractors charge $75 to $125 per hour in most markets, with metropolitan areas trending higher. A standard replacement in a home with accessible ducts takes two to four days for a two-person crew, while complex projects with hidden ducts or multi-story routing can take five days or more.

Duct accessibility is the single biggest labor cost variable. Open basements and accessible attics allow technicians to work efficiently with standard tools and minimal preparation. When ducts run inside finished walls, above drywall ceilings, or under concrete slabs, the crew must first open these surfaces, then perform the duct work, and finally patch and restore the surfaces afterward. This demolition and restoration work can add $1,000 to $5,000 to the project depending on the extent of the openings required.

The condition of the existing ductwork also affects labor. Old metal ducts that are heavily corroded or sealed with asbestos-containing tape require careful removal procedures that take longer and may involve hazardous material handling fees. Flexible duct that has collapsed or disconnected is generally faster to remove since it can be pulled out in sections rather than disassembled piece by piece.

Additional Costs to Plan For

Several common add-on costs fall outside the base replacement estimate. Building permits cost $50 to $250 for most ductwork replacement projects, though some jurisdictions waive permit requirements for like-for-like replacements. An HVAC inspection after installation runs $100 to $200 and is required in many areas before the system can be reconnected.

If your existing system is undersized or oversized for your home, the replacement project is an opportunity to correct the sizing. Adding or removing supply registers costs $50 to $150 per register. Resizing trunk lines to match your HVAC system capacity can add $500 to $1,500 depending on how much reconfiguration is needed. Our guide on ductwork sizing explains why properly sized ducts matter for system performance.

Duct insulation is an additional cost if you are replacing uninsulated metal ducts in unconditioned spaces. Wrapping existing metal ducts with R-6 or R-8 insulation costs $2 to $4 per linear foot, while choosing pre-insulated flex duct builds the insulation cost into the material price. Our ductwork insulation cost guide covers insulation options in detail.

How to Get Accurate Quotes

Getting accurate quotes for ductwork replacement requires having contractors physically inspect your home. Phone estimates and online calculators provide rough ballpark figures, but they cannot account for the accessibility issues, routing complications, and existing system conditions that drive real-world pricing.

Request quotes from at least three licensed HVAC contractors. Each quote should include the type and quantity of duct material, the number and sizes of registers being installed, any demolition or restoration work required, permit costs, and the projected timeline. Comparing quotes on these specifics, rather than just the bottom-line number, helps you identify which contractors are thorough and which might be lowballing to win the job and adding change orders later.

Ask each contractor whether they recommend a duct pressure test before and after the work. A pre-replacement test establishes baseline leakage so you can verify the new system is significantly tighter. A post-replacement test confirms the installation meets industry standards for air delivery. These tests cost $150 to $500 but provide objective evidence that you received the performance you paid for.