Specifications
- Inlet Diameter: 2" to 48"
- Outlet Diameter: 2" to 48"
- Length: 4" to 120" (10 ft)
- Materials: Galvanized Steel, Aluminum, Stainless Steel
- Gauges: 26, 24, 22, 20
- Connections: Raw, Slip, Drive, TDC, Flanged
Standard Round Duct Sizes & Pricing
| Dia In | Dia Out | Length | Material | Gauge | Inlet | Outlet | Price | Order |
|---|---|---|---|---|---|---|---|---|
| 4" | 4" | 12" | Galvanized | 26 ga | Slip / Slip | $27.73 | ||
| 5" | 5" | 12" | Galvanized | 26 ga | Slip / Slip | $30.66 | ||
| 6" | 6" | 12" | Galvanized | 26 ga | Slip / Slip | $33.59 | ||
| 6" | 6" | 24" | Galvanized | 26 ga | Slip / Slip | $51.19 | ||
| 6" | 6" | 36" | Galvanized | 26 ga | Drive / Drive | $70.78 | ||
| 7" | 7" | 24" | Galvanized | 26 ga | Slip / Slip | $57.05 | ||
| 8" | 8" | 24" | Galvanized | 26 ga | Slip / Slip | $62.91 | ||
| 8" | 8" | 36" | Galvanized | 26 ga | Drive / Drive | $88.37 | ||
| 8" | 8" | 48" | Galvanized | 26 ga | Drive / Drive | $111.83 | ||
| 10" | 10" | 24" | Galvanized | 26 ga | Drive / Drive | $76.64 | ||
| 10" | 10" | 36" | Galvanized | 26 ga | Drive / Drive | $105.96 | ||
| 10" | 10" | 48" | Galvanized | 26 ga | Drive / Drive | $135.29 | ||
| 10" | 10" | 60" | Galvanized | 24 ga | Drive / Drive | $197.93 | ||
| 12" | 12" | 24" | Galvanized | 26 ga | Drive / Drive | $88.37 | ||
| 12" | 12" | 36" | Galvanized | 26 ga | Drive / Drive | $123.56 | ||
| 12" | 12" | 48" | Galvanized | 24 ga | Drive / Drive | $190.89 | ||
| 12" | 12" | 60" | Galvanized | 24 ga | TDC / TDC | $237.11 | ||
| 14" | 14" | 48" | Galvanized | 24 ga | TDC / TDC | $223.04 | ||
| 16" | 16" | 48" | Galvanized | 22 ga | TDC / TDC | $313.49 | ||
| 18" | 18" | 48" | Galvanized | 22 ga | TDC / TDC | $348.67 | ||
| 20" | 20" | 60" | Galvanized | 22 ga | Flanged / Flanged | $479.82 | ||
| 24" | 24" | 60" | Galvanized | 20 ga | Flanged / Flanged | $751.72 | ||
| 10" | 10" | 48" | Aluminum | 26 ga | Slip / Slip | $213.92 | ||
| 10" | 10" | 48" | Stainless | 26 ga | Slip / Slip | $426.50 | ||
| 6" | 4" | 24" | Galvanized | 26 ga | Slip / Slip | $45.32 |
Custom Round Duct — Spiral & Snap-Lock Fabrication
Round duct is the most aerodynamically efficient shape for air distribution, producing lower friction loss per CFM than rectangular sections. Our round duct sections are available with independent inlet and outlet diameters, making them equally suited for straight runs and gradual round-to-round transitions. Each piece is fabricated from a single sheet with a spiral or longitudinal seam, depending on diameter and gauge.
Residential & Light Commercial
Standard residential supply and return runs use 4" to 12" diameter round duct in 26 gauge galvanized steel with slip connections. Round duct is preferred for branch runs off rectangular trunk lines due to its lower turbulence and quieter airflow. Common sizes include 6" and 8" for bedrooms and bathrooms, and 10" to 12" for main living areas.
Commercial & Industrial
Larger commercial systems use 14" to 48" round duct in 24 to 20 gauge with TDC or flanged connections for higher static pressure ratings. Round duct is the standard for rooftop units, exhaust systems, and laboratory fume hood connections. Its inherent rigidity reduces the need for external reinforcement compared to rectangular duct of equivalent cross-sectional area.
Material Selection for Round Duct
Galvanized steel ($1.25/sqft) handles 95% of standard installations. Aluminum ($2.10/sqft) is preferred for rooftop and suspended systems where weight is critical—65% lighter than steel at equivalent gauge. Stainless steel ($4.25/sqft) is required for kitchen exhaust, pharmaceutical clean rooms, and corrosive environments. All materials are available in 26 through 20 gauge.
Frequently Asked Questions
What diameter range do you offer for round duct?
We fabricate round duct from 2 inches to 48 inches in diameter, in any length from 4 to 120 inches.
Is round duct more efficient than rectangular?
Round duct has lower friction loss per CFM and requires less material for the same airflow capacity. It is preferred where space allows.
What connection types work with round duct?
Round duct uses slip (crimped end), raw, or beaded connections. We can also fabricate flanged ends for high-pressure systems.