Supply Air Plenum Cost: 2026 Installed Price Calculator
Mike Martin, MA CSL, is the founder and construction cost editor of RemodelingExpense. His residential construction experience informs the site’s cost research, calculators, and homeowner project guidance.
Supply air plenum cost ranges from $500 – $2,800 per plenum installed, with higher prices when the job needs custom sheet metal, trunk duct changes, branch takeoffs, dampers, sealing, or difficult HVAC access.
A supply air plenum is the supply-side air box that sends heated or cooled air from the furnace or air handler into the duct system. It is different from a return air plenum, which brings air back into the equipment.
Use this calculator for supply air plenum replacement, furnace supply boxes, air handler supply plenums, trunk duct connections, branch takeoffs, damper work, and supply-side duct repairs.
Cost Calculator
Supply Air Plenum Cost Calculator
Estimate installed supply air plenum pricing based on plenum count, sheet metal size, trunk connections, takeoffs, dampers, access, sealing, labor, and local cost factors.
Your estimated cost
For 1 plenum
$500 – $2,800
About $500 – $2,800 per plenum
Use your estimate as a starting point, then compare real prices from local contractors.
| Cost item | Low estimate | High estimate |
|---|---|---|
| Materials | $175 | $1,540 |
| Labor | $325 | $1,260 |
| Estimated supply air plenum cost | $500 | $2,800 |
| Installed cost per plenum | $500 | $2,800 |
Why your price may change
- Local labor rates vary.
- Material quality affects the price.
- Old material removal, repairs, permits, or code updates can add cost.
- Hard-to-reach areas, complex layouts, rush jobs, or premium contractors may cost more.
Estimate includes local labor adjustments and may differ slightly from rounded national cost examples.
Supply Air Plenum Cost vs Value
Supply Air Plenum may recover about 5%–20% of its cost.
Bottom line: Supply air plenum cost depends on sheet metal size, furnace or air handler fit, trunk duct connections, branch takeoffs, dampers, access, air sealing, airflow balance, and local HVAC labor rates.
Worth it: Homeowners replacing a damaged, leaking, undersized, or poorly sealed supply-side plenum near the furnace or air handler.
Skip it: If only one room has weak airflow, a branch duct or register issue may be the cheaper fix.
ROI ranges are planning estimates and should not be treated as an appraisal. This is only an estimate. Real resale value depends on your home, neighborhood, market, project quality, and buyer demand.
Contractor Reality Check
A supply air plenum affects how conditioned air leaves the furnace or air handler. If the box is undersized, leaky, poorly sealed, or packed with bad takeoffs, some rooms may never get the airflow they need.
My rule of thumb: ask whether the quote includes sheet metal fabrication, trunk duct connections, branch takeoffs, dampers, sealing, access work, and a basic airflow check.
What to Confirm Before You Sign
- Plenum size: confirm the new supply box is sized for the furnace or air handler output.
- Sheet metal: ask whether custom fabrication is included.
- Trunk connections: confirm how the main supply ducts connect to the plenum.
- Branch takeoffs: ask whether existing takeoffs will be reused, moved, sealed, or replaced.
- Dampers: confirm whether balancing dampers are included where needed.
- Air sealing: make sure seams, collars, and duct connections are sealed after installation.
- Buffer: budget 10% to 20% for custom metal, tight access, duct transitions, takeoff changes, dampers, or sealing.
Surprise Costs That Move the Price
| Item | Why It Adds Cost | Typical Add |
|---|---|---|
| Custom sheet metal | Odd equipment sizes, low ceilings, or unusual duct layouts may require a fabricated supply box. | $300 – $1,700+ |
| Trunk duct tie-in | Main supply ducts may need transitions, resizing, or reconnection. | $300 – $1,800+ |
| Branch takeoffs | Adding, moving, or replacing takeoffs can increase labor and material cost. | $100 – $500+ each |
| Dampers | Balancing dampers help control airflow to different duct runs. | $75 – $300+ each |
| Air sealing | Leaky collars, seams, and transitions can waste airflow before it reaches the rooms. | $150 – $900+ |
Supply Air Plenum Cost by Type
| Type | Installed Cost per Plenum | Best For |
|---|---|---|
| Basic supply air plenum | $500 – $1,300 | Simple replacements with easy furnace or air handler access. |
| Custom supply plenum | $1,000 – $2,800+ | Systems that need fabricated sheet metal or odd-size transitions. |
| Supply plenum with takeoffs | $900 – $3,200+ | Jobs that include new or revised branch duct connections. |
| Supply plenum with dampers | $1,100 – $3,500+ | Systems that need better airflow control to different duct runs. |
| Supply air plenum repair | $300 – $1,300+ | Fixing loose panels, air leaks, poor seams, or minor takeoff issues. |
Is a Supply Air Plenum Worth Replacing?
A supply air plenum is worth replacing when the existing box is leaking, damaged, undersized, poorly sealed, or causing uneven airflow from the furnace or air handler into the duct system.
Skip it: If only one room has weak airflow, a branch duct or register issue may be the cheaper fix.
References – Supply Air Plenum Cost
- Ductwork Reference: U.S. Department of Energy
- Duct Sealing Reference: ENERGY STAR
- Equipment Reference: Air-Conditioning, Heating, and Refrigeration Institute
- Labor Wage Data: Occupational Employment and Wage Statistics, U.S. Bureau of Labor Statistics
- Labor Burden Data: Employer Costs for Employee Compensation, U.S. Bureau of Labor Statistics
Last Updated: 6/21/26
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