Specifications
- Input Width: 1" to 36"
- Input Height: 1" to 36"
- Output Width: 1" to 36"
- Output Height: 1" to 36"
- Length: 1" to 36"
- Materials: Galvanized Steel
- Connections: Raw, Slip, Drive, FoldOut, DoubleFoldOut
Standard Duct Reducer Sizes & Pricing
| Input W×H | Output W×H | Length | Input Joint | Output Joint | Price | Order |
|---|---|---|---|---|---|---|
| 8"×8" | 6"×6" | 6" | Raw | Raw | $11.20 | |
| 10"×6" | 8"×6" | 6" | Slip | Slip | $13.40 | |
| 10"×8" | 8"×6" | 8" | Slip | Slip | $15.20 | |
| 10"×8" | 8"×8" | 6" | Slip | Slip | $14.40 | |
| 12"×8" | 10"×8" | 8" | Slip | Slip | $16.80 | |
| 12"×10" | 10"×8" | 8" | Slip | Slip | $18.20 | |
| 12"×10" | 8"×8" | 10" | Drive | Slip | $20.60 | |
| 12"×12" | 10"×10" | 8" | Drive | Slip | $21.40 | |
| 14"×10" | 12"×8" | 10" | Drive | Slip | $22.80 | |
| 14"×10" | 10"×8" | 12" | Drive | Slip | $25.40 | |
| 14"×12" | 12"×10" | 10" | Drive | Drive | $28.60 | |
| 16"×10" | 14"×10" | 8" | Drive | Drive | $26.20 | |
| 16"×12" | 12"×10" | 12" | FoldOut | Slip | $34.80 | |
| 18"×12" | 14"×10" | 12" | FoldOut | Drive | $38.60 | |
| 20"×12" | 16"×10" | 12" | FoldOut | FoldOut | $46.20 | |
| 20"×14" | 14"×12" | 14" | FoldOut | FoldOut | $54.80 | |
| 24"×12" | 18"×10" | 14" | DoubleFoldOut | FoldOut | $62.40 | |
| 24"×18" | 18"×12" | 16" | DoubleFoldOut | FoldOut | $74.60 | |
| 24"×24" | 18"×18" | 18" | DoubleFoldOut | DoubleFoldOut | $98.40 | |
| 30"×18" | 24"×14" | 18" | DoubleFoldOut | DoubleFoldOut | $112.50 | |
| 36"×24" | 24"×18" | 24" | DoubleFoldOut | DoubleFoldOut | $145.00 |
Custom Duct Reducers — Precision Size Reduction Fittings
Duct reducers are tapered fittings designed specifically to step down the cross-section of rectangular ductwork. While functionally similar to transitions, reducers are optimized for the narrowing direction—larger input flowing to smaller output. Each reducer is fabricated from four precision-cut trapezoidal panels that form a smooth taper, minimizing pressure loss and air noise at the size change point.
Why Custom Reducers Matter
Field-fabricated reducers made by notching and folding straight duct create irregular tapers that generate turbulence, noise, and unnecessary pressure drop. Our CNC-cut reducers provide mathematically precise geometry with consistent taper angles on all four sides. The result is quieter operation, lower static pressure loss, and a professional appearance.
Reducer Sizing Guidelines
For optimal airflow, the reducer length should equal at least 1.5 times the difference between the larger and smaller dimensions. A 14"×10" to 10"×8" reducer should be at least 6" long (1.5 × 4"). For noise-sensitive installations in occupied spaces, use a length of 2.5 times the size difference. ASHRAE guidelines recommend a maximum taper angle of 15° for duct reductions.
Trunk Line Step-Downs
The most common application is residential and commercial trunk-line step-downs. As branch takeoffs remove airflow from the trunk, the remaining trunk section can be reduced to maintain air velocity and save material. A typical residential system might step down from 14"×10" to 12"×8" to 10"×8" to 8"×6" along a 40-foot trunk run, with reducers at each branch takeoff location.
Frequently Asked Questions
How long should a duct reducer be?
For optimal airflow, the reducer length should equal at least 1.5 times the difference between the larger and smaller dimensions. For noise-sensitive areas, use 2.5 times the size difference.
What is the difference between a reducer and a transition?
A reducer is optimized for narrowing duct size (larger to smaller). A transition can change size in either direction and allows fully independent width and height changes on each end.
What joint types are available?
Raw, Slip, Drive, FoldOut, and DoubleFoldOut. Input and output joints can be set independently.