Precision-engineered galvanized steel reducers that transition between different duct diameters — ensuring smooth, continuous airflow with zero turbulence. Available in concentric and eccentric configurations from 4″×3″ to 18″×16″.
SIDCO Reducers are manufactured using 22-gauge G60 galvanized or Paintgrip steel to provide a reliable, low-turbulence transition between different duct diameters. Whether you need to step down from a large main duct to a smaller branch run, or increase diameter toward a plenum, our reducers connect clamp-together spiral ducting with precision-formed ends for a secure, airtight fit.
Both inlet and outlet share the same centerline axis. Ideal for straight duct runs where balanced airflow and symmetrical diameter reduction is required. The most commonly specified reducer for commercial HVAC systems.
Inlet and outlet are offset — one side remains flat while the other tapers. Used where the bottom or top of the duct must remain level, such as when duct runs must maintain ceiling height or fit within constrained spaces.
Each reducer is engineered to exact inlet-to-outlet tolerances — ensuring a smooth taper angle and flush connection on both duct ends.
Smaller sizes (up to 10″) are die-stamped for tight tolerances. Larger inlet sizes (12″+) are roll-fabricated for structural strength and consistency.
Every reducer is checked for taper uniformity, seam integrity, and G60 coating coverage before leaving our Memphis facility.
Stocked in Memphis, TN for rapid fulfillment across a wide range of standard size combinations. Order online or by phone.
Stepping down from large main supply ducts to smaller branch runs feeding individual zones, rooms, and diffuser drops.
Transitioning between heavy-gauge main duct runs and smaller branch ventilation lines in warehouses and manufacturing facilities.
Specified by mechanical engineers on new builds to accommodate duct sizing changes across different floor levels and zones.
Adapting legacy ductwork to new equipment sizes or adding branch runs to an existing system without full replacement.
Precisely controlling airflow velocity in cooling systems by adjusting duct cross-section at key transition points.
Used in both supply and exhaust networks to match duct sizing to fan outlet dimensions and terminal device requirements.
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