Ductwork for swamp cooler conversion: reuse or replace?
Why ducts decide the price and the comfort of a conversion.
Quick answer: Swamp cooler ducts can often be partly reused for refrigerated air, but they usually need sealing, insulation, and a return-air path that swamp cooler homes typically lack. Reusable ducts are why published conversion ranges can start as low as $3,800, according to AFM.
How swamp cooler ducts differ
- Large airflow. Evaporative coolers move a lot of air at low pressure, so their ducts and grilles tend to be large.
- Usually no return. A swamp cooler pushes air in and relies on open windows or relief vents to let it out. Refrigerated air recirculates indoor air and needs return grilles and ducts.
- Often uninsulated. Ducts in a hot attic lose cooling unless they are sealed and insulated.
- Down-draft layouts. Roof-mounted coolers often drop air straight down through a ceiling opening, which may not suit a central air system.
What a contractor will check
- Duct size, condition, leaks, and insulation
- Whether the existing layout can reach every room
- Where return air will come from
- The roof or wall opening where the old cooler sat
Reuse, repair, or replace
| Option | When it fits | Cost effect |
|---|---|---|
| Reuse | Ducts are sound and sized well enough | Lower, per AFM’s published range |
| Repair and modify | Leaks, missing insulation, or added returns | Moderate |
| Replace | Damaged or badly sized ducts | Higher end of the ranges |
Ask the contractor to say in writing which option the quote assumes.
Frequently asked questions
Can swamp cooler ducts be used for central air?
Often partly. They are sized for high airflow, but they may need sealing, insulation, and changes. The contractor decides after inspecting them.
Why does central air need return ducts?
A refrigerated system recirculates the same indoor air, so it needs a path for air to return to the unit. A swamp cooler pushes fresh air in and lets it escape through open windows, so many swamp cooler homes have no return path at all.
Do I need to insulate the ducts?
Ducts in an attic or other unconditioned space should be sealed and insulated, because refrigerated air loses cooling quickly in hot spaces. Ask what the contractor plans for yours.
Will new ducts raise the price?
Yes. Reusing ducts is a main reason published conversion ranges start lower. See the cost guide.