Air Flow Products RE2018 Duct Reducer Increaser 20 to 18

Product Description

The AIR FLOW PRODUCTS RE2018 is a duct reducer-increaser fitting designed to transition between 20-inch and 18-inch round duct diameters in forced-air HVAC systems. This type of fitting allows ductwork installers to step down or step up airflow paths where duct sizing changes along a trunk or branch run. The RE2018 maintains airflow continuity across the diameter transition, making it a practical component in both new construction and retrofit duct system work. HVAC sheet metal installers and duct fabricators are the primary trades that specify and install this fitting.

This reducer-increaser is suited for residential and light commercial forced-air installations where a 20-inch to 18-inch duct transition is required. Typical applications include main trunk reductions as a duct run extends further from the air handler, or branch takeoff configurations where duct sizing must be adjusted to balance system static pressure. The fitting is identified by the AFP designation RE2018 and corresponds to the 85-series product line within the AIR FLOW PRODUCTS catalog.

Key Features

• Transitions between 20-inch and 18-inch round duct diameters
• Suitable for trunk reductions and branch run adjustments in forced-air systems
• Part of the AIR FLOW PRODUCTS 85-series duct fitting line
• Supports both supply and return duct configurations depending on installation layout

Compatibility

Designed as an OEM-style duct fitting replacement or new-install component for forced-air HVAC systems requiring a round duct transition from 20 inches to 18 inches in diameter.

Installation Notes

Installation is performed by licensed HVAC technicians or qualified sheet metal installers following applicable mechanical codes such as SMACNA duct construction standards and local mechanical codes. Shut down the air handling unit and confirm the system is de-energized before cutting or connecting ductwork sections. Secure the fitting with sheet metal screws and seal all joints with UL 181-listed mastic or foil tape to prevent air leakage. Verify the direction of airflow relative to the reducer orientation before final fastening.

Technical Specifications

• Inlet Diameter: 20 inches
• Outlet Diameter: 18 inches
• Series: 85

Standard Information

• Brand: AIR FLOW PRODUCTS
• Manufacturer Part Number: RE2018