Supply Diffusers

Curbs Plus Supply Diffusers are engineered for reliable air delivery from rooftop units into conditioned spaces.

Built from heavy-duty materials and fully assembled, these diffusers simplify installation and help ensure balanced, adjustable airflow across a wide range of commercial HVAC applications.

Why Choose Curbs Plus Supply Diffusers

✔ Robust Construction – Heavy-gauge G-90 galvanized steel and quality insulation mean longer life and reliable performance.

✔ Balanced Airflow Control – Drum louvers and adjustable grilles help tailor supply patterns to your space.

✔ Fully Assembled Units – Arrive ready for install, saving time and reducing field labor.

✔ Versatile Models – Choose from 2-, 3-, 4-, or 6-way, low profile, slant face, and vertical face designs to suit project needs.

✔ Comprehensive Documentation – Plenum-diffuser specs and drawings are available for accurate planning and easy specifying.

✔ Engineered Options Available – Compatible with engineered curb and duct packages for a complete HVAC solution.

DLPD 2-Way Corner Drum Louver Plenum-Diffuser

A standard two-direction supply diffuser designed for balanced airflow in straight plenum applications.

  • Construction: G-90 galvanized steel.

  • Airflow Control: Vertical and horizontal adjustable drum louvers with internal turning vanes.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars provided.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled plenum-diffuser.

  • Capacity Range: ~1,200–16,000 CFM (up to ~40 ton).

DLPD-2Way

DLPD 2-Way Drum Louver Plenum-Diffuser

Designed to distribute supply air in three directions for improved coverage in larger spaces.

  • Construction: G-90 galvanized steel.

  • Airflow Control: Three-direction adjustable drum louvers with quadrant turning vanes.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled plenum-diffuser.

  • Capacity Range: ~1,200–16,000 CFM (up to ~40 ton).

DLPD-2way

DLPD 3-Way Drum Louver Plenum-Diffuser

Designed to distribute supply air in three directions for improved coverage in larger spaces.

  • Construction: G-90 galvanized steel.

  • Airflow Control: Three-direction adjustable drum louvers with quadrant turning vanes.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled plenum-diffuser.

  • Capacity Range: ~1,200–16,000 CFM (up to ~40 ton).

DLPD-3way

DLPD 4-Way Drum Louver Plenum-Diffuser

Provides uniform, four-direction airflow from a single central plenum.

  • Construction: G-90 galvanized steel.

  • Airflow Control: Four-way adjustable drum louvers with turning vanes.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled plenum-diffuser.

  • Capacity Range: ~1,200–16,000 CFM (up to ~40 ton).

DLPD-4way

DLPD 6-Way Drum Louver Plenum-Diffuser

Ideal for large rooftop units requiring multi-directional airflow distribution.

  • Construction: Heavy-duty G-90 galvanized steel.

  • Airflow Control: Six-direction adjustable drum louvers with internal turning vanes.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars provided.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled plenum-diffuser.

  • Capacity Range: ~2,000–16,000 CFM (5–40 ton).

LPPD – Low Profile Plenum-Diffuser

A compact diffuser solution for applications with limited ceiling or plenum height.

  • Construction: G-90 galvanized steel.

  • Airflow Control: Adjustable vertical and horizontal deflection grilles.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled low-profile plenum-diffuser.

  • Capacity Range: Varies by configuration.

SFPD – Slant Face Plenum-Diffuser

Angled discharge design helps project air outward and downward into the occupied space.

  • Construction: G-90 galvanized steel.

  • Airflow Control: Adjustable deflection grilles on a slanted face.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled plenum-diffuser.

  • Capacity Range: Varies by unit size.

VFPD – Vertical Face Plenum-Diffuser

A straight-discharge diffuser for controlled, forward airflow patterns.

  • Construction: G-90 galvanized steel.

  • Airflow Control: Adjustable vertical deflection grilles.

  • Insulation: 1″, 1½ lb duct liner.

  • Connections: TDC duct collars.

  • Mounting: 3/8″ threaded inserts standard.

  • Installation: Fully assembled plenum-diffuser.

  • Capacity Range: Varies by configuration.

VFPD

Typical Applications

Curbs Plus Supply Diffusers are commonly used for:

  • Distributing conditioned air from rooftop units

  • Matching airflow patterns to room layouts

  • Low-plenum or tight-ceiling applications

  • Large commercial and institutional spaces

  • Comfort-focused air distribution designs

Designed for Airflow Control & Comfort

Supply Diffusers deliver consistent, controlled airflow to occupied spaces. Their adaptable designs support efficient HVAC performance and improved occupant comfort.