Ductwork Repair, Sealing and Replacement

Signs Your Ducts Need Attention

Ducts carry cooled air from the air handler to every room. When they leak, sag or get crushed, that air never arrives.

Phoenix cooling runs for months, so weak spots show up fast. Watch for:

• Rooms that stay hot or vents with weak airflow
• Torn or sagging flex duct, loose joints, failing tape or insulation
• Dust, hot spots or rising bills with no equipment fault

These are prompts for an inspection, not a diagnosis.

Older ductwork in Mesa, Glendale or Chandler homes may be near the end of its service life, and an inspector can tell you whether sealing still works or a run needs replacing. Attic heat is the usual culprit. The attic duct replacement guide explains when sealing stops being enough.

Waiting rarely makes it cheaper.

A small disconnect left alone keeps dumping cooled air into the attic, and the AC runs longer to compensate.

Sound familiar? One room never cools. You taped a loose joint. It held for a while. Now the bill is climbing and the AC runs nonstop.

What Drives Duct Repair and Replacement Cost in Phoenix

Duct work is priced by the job, not by a flat rate. Home size, attic or slab access, duct material, insulation, the number of runs and whether the air handler also needs work all move the total.

Price factors

What moves the price of duct work

• 01

  Home size

  Larger homes need more duct and more runs

• 02

  Access

  Attic or slab access changes the labor involved

• 03

  Duct material

  The material chosen changes the total

• 04

  Insulation

  Added or replaced insulation adds to the job

• 05

  Number of runs

  More runs mean more repair or replacement work

• 06

  Air handler

  Work on the air handler is added to the duct total

Phoenix-area HVAC companies' own websites, checked October 2026, show these figures for related work:

Four of the 10 listings say the diagnostic fee is waived or credited when you approve the repair.

Duct sealing may also earn an APS rebate. The program lists "Duct Sealing: $250 per system."^[1] Confirm current terms before you book.

Get several written quotes that itemize scope: how many runs, what material, what insulation, and whether sealing and testing are included. For attic-specific cost factors, see the attic duct guide.

Pro tip

Ask every contractor to quote the same scope, including runs, material, insulation and testing, so the written quotes compare line for line.

How a Duct Replacement Job Works, Step by Step

A duct replacement job runs in five steps, summarised here and detailed below.

Step by step

The five steps at a glance

1. 1

   Inspection

   The contractor checks ducts, registers and the air handler.

2. 2

   Design and sizing

   New runs are sized to move proper airflow.

3. 3

   Removal

   Old, damaged duct comes out.

4. 4

   Installation

   New insulated duct goes in with sealed joints.

5. 5

   Testing

   The crew checks airflow at each register.

1. Inspection and airflow assessment. The contractor checks existing ducts, registers and the air handler, then confirms scope in writing.
2. Design and sizing. New runs must move proper airflow. Ask how sizing was calculated.
3. Removal. Old, damaged duct comes out of the attic, crawl space or ceiling.
4. Installation. New insulated duct goes in, with joints and connections sealed.
5. Testing. The crew checks airflow at each register.

Expect a written contract showing the license number plus start and completion dates.

Attic work in July is brutal for crews and homeowners alike.

Spring and winter scheduling in Scottsdale or Gilbert often means easier access and more flexible calendars, since winter is the slower season for HVAC.

Ask whether the job needs a permit. Rules differ between Phoenix, Mesa, Scottsdale and county areas, so the contractor should tell you which applies. Permits for AC swaps are covered in this guide.

Hiring a Licensed Duct Contractor in Arizona

Arizona's Registrar of Contractors (ROC) licenses HVAC contractors. The license class must cover the work in your contract, and the record should show an active license.

Before you sign:

• Search the contractor in the ROC license lookup and confirm the license is active
• Call the phone number on the ROC record, not just the one on the ad
• Ask for proof of insurance; a license alone does not guarantee coverage beyond workers' compensation
• Ask how duct sizing was calculated
• Get a written, itemized scope with license number and dates

Unlicensed work is exempt only under $1,000 and other limits, so a duct replacement almost always needs a licensed pro.

Checklist

Questions and checks before you sign

0 of 5 ticked

• Is the ROC license active and does its class cover this work?
• Does the phone number on the ROC record match the one on the ad?
• Can they show proof of insurance?
• How was the duct sizing calculated?
• Is the scope written and itemized, with license number and dates?

Tick them off as you go. Nothing is saved or sent.

Red flags: no written contract, vague scope, pressure to skip permits, or a "tape it up" fix for crushed or failing flex duct.

Our guides on verifying an HVAC license and questions to ask before hiring walk through the details. Then compare the licensed duct pros serving Peoria, Surprise, Buckeye and across the valley below.