Flexible Duct / Duct Board / Boots & Boxes

Save on in-stock Flexible Duct, Duct Board, and Boots & Boxes for fast, code-ready HVAC installs in homes, rentals, and light commercial spaces.

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Flexible Duct / Duct Board / Boots & Boxes

Get the right air path components for new runs, repairs, and extensions. Flexible insulated duct routes supply and return air through attics, crawlspaces, and between joists. Register boots and boxes make tight, leak-resistant transitions to grilles. Duct board sheets let you build quiet plenums, trunks, and distribution boxes without sheet metal. Choose the subcategory that fits your task and keep projects moving with in-stock, budget-friendly parts.

These components are not rated by SEER2, HSPF2, BTU/tonnage, or refrigerant; they work with any properly sized HVAC system. Focus on correct diameters, R-value, and airtight sealing to maintain airflow and comfort. Our everyday prices range from $14 to $44, making it easy to stock up for multi-room jobs while meeting code and manufacturer specifications.

DIY-capable homeowners appreciate simple connections and clear labeling, while licensed contractors and property managers rely on consistent sizing for fast change-outs. Use flexible duct for branch runs to registers, boots and boxes to adapt to standard grille openings, and duct board to fabricate plenums and distribution boxes that fit your layout.

Top Brands for Flexible Duct / Duct Board / Boots & Boxes

We stock Quietflex flexible duct, Crown supply and return boots and boxes, Metal Shop fittings and transitions, plus duct board options from Johns Manville to match your job’s spec.

Frequently Asked Questions

  • How do I choose between flexible duct and duct board for my application?

    Use flexible duct for branch runs and tight spaces; use duct board to build plenums, trunks, and distribution boxes where rigid, insulated air paths are needed.

  • What size register boot or box do I need for my supply or return?

    Match the boot’s face size to the grille/register opening and the collar to your duct diameter. Final sizing should follow Manual D or your engineer’s design.

  • Are Quietflex ducts rated for use in unconditioned spaces like attics?

    Most Quietflex insulated ducts are UL 181 listed and commonly approved for attics and crawlspaces when installed per code. Verify the specific model’s listing and local requirements.

  • What are best practices for installing flexible insulated duct to maintain airflow?

    Keep runs as short and straight as possible, pull the inner core taut, avoid kinks, and use sweeping bends. Properly support and seal every connection.

  • How do I seal and insulate connections between boots, boxes, and duct board?

    Mechanically fasten the inner core, apply mastic or UL 181 tape to the joint, then pull the insulation jacket over the collar and secure with a listed drawband or clamp.

  • Can these components be used in light commercial applications and what codes apply?

    Yes, they’re widely used in light commercial work. Follow the IMC/IRC, energy code R-value requirements, and manufacturers’ instructions for listings such as UL 181.

  • What diameter flexible duct should I choose for my CFM?

    Size by design using Manual D or equivalent. As a rough start, many systems use 6 in for ~80-120 CFM and 8 in for ~160-250 CFM; confirm for your static pressure and layout.

  • Can I build a plenum from duct board to replace a metal trunk?

    Yes, duct board is commonly fabricated into plenums and trunks. Use approved adhesives, fasteners, and closure methods per the board manufacturer.

  • How should flexible duct be supported?

    Support per code and manufacturer; many guidelines call for hangers at about 4 ft intervals with 1.5 in wide straps, keeping the duct round and off sharp edges.

  • Do these parts affect SEER2, BTU, tonnage, or refrigerant selection?

    They are not rated for SEER2, BTU/tonnage, or refrigerant. However, correct sizing and airtight installation help your equipment deliver its designed efficiency and comfort.

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