HVAC Ducting & Ventilation Supplies

Name: HVAC Ducting & Ventilation Supplies
Brand: Voomi Supply
Rating: 4.9 (124 reviews)

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Voomi Supply carries HVAC ducting and ventilation supplies from Gray Metal South, Southwark Metal, TRUaire, Broan-NuTone, Panasonic and DuroDyne, in rectangular and round duct fittings, register boots, return air grilles, wall caps, vent tee caps, duct hangers, fans and ventilators across galvanized steel gauges and many sizes. Ducting carries conditioned air from the equipment to each room, and ventilation parts move stale air out and fresh air in, so the right fitting, sealing method and vent type keep airflow balanced and exhaust safe. Every order ships with Voomi's 30-day return policy and free help matching a part to your system.

Where to Find Each Part

Collection	What it covers	Typical job
Ductwork & sheet metal	Trunk duct, register boots, plenums, reducers, caps and hangers	Building or repairing a duct system
Flex duct	Flexible duct for tight or irregular runs	Connecting trunks to outlets
Grilles, registers & diffusers	Return and supply openings in rooms	Air delivery and return
Dampers	Dampers that open or close airflow in a duct	Balancing or isolating a run
Blowers & inline duct fans	Blowers, blower motors and inline fans	Moving air through the duct
Fan blades	Replacement blades for fans and condensers	Fan repair
Commercial ventilation	Ventilation equipment for commercial buildings	Exhaust and fresh air
Air vents & roof maintenance	Wall caps, roof vents and related components	Exhaust terminations
Vent pipes & fittings	Vent pipe and fittings for fuel-burning appliances	Flue and combustion venting

Complete Ducting Solutions

Our selection of ducting products supports efficient airflow for residential, commercial, and industrial HVAC systems, ensuring consistent comfort and performance.

Reliable Air Ducting Options

From round to rectangular, our air ducting materials are designed to reduce airflow resistance, minimize noise, and promote even air distribution.

Ventilation Ducting for Healthy Airflow

Proper ventilation ducting is essential for removing stale air, odors, and contaminants. We carry options suitable for exhaust, fresh air intake, and return air systems.

Rigid vs Flexible Ducting

	Rigid (sheet metal)	Flexible
Best for	Long, straight runs with minimal airflow loss	Tight spaces and complex layouts
Airflow	Low resistance	Higher resistance. In a Texas A&M study, a 6 in flex duct at 4 percent compression moved about 70 CFM against about 110 CFM for rigid at 0.1 in. w.c., with nearly identical flow at 0 percent compression.
Installation	Cut, fit and seal each joint	Fast to route, but keep it fully stretched and avoid sags and tight bends

Ductwork Materials and Gauges

Galvanized steel is sold by gauge, and a higher gauge number means thinner metal. Gauge numbers differ by material, so 22 gauge aluminum is thinner than 22 gauge galvanized steel.

Gauge	Galvanized thickness	Where you see it
22 ga	0.0336 in	Heavier duct and fittings
24 ga	0.0276 in	Duct and fittings
26 ga	0.0217 in	Duct and fittings
28 ga	0.0187 in	Lighter fittings, such as 28 ga vent tee caps
30 ga	0.0157 in	Light duty fittings, such as 30 ga boots

Sealing and Insulating Ductwork

Topic	What to know
Sealing material	Use mastic or metal tape that meets UL 181. Cloth-backed duct tape can dry out and fail quickly.
Wide seams	Cover seams wider than 1/8 in with fiberglass mesh tape before applying mastic
Leakage	Typical leakage in code-built homes is around 10 percent. On a 1,000 CFM system that is roughly 100 CFM lost.
Insulation	The 2009 IECC calls for at least R-8 on supply ducts and R-6 on return ducts in unconditioned space. Compression lowers the R-value.

Venting Categories for Fuel-Burning Appliances

Appliance venting categories depend on whether the vent runs under negative or positive pressure and whether the flue gas condenses. Always follow the appliance manufacturer and local code.

Category	Pressure and condensation	Typical vent materials
I	Negative pressure, non-condensing	B-vent (double-wall, gas only), flexible liners, masonry chimney liners, and single-wall pipe as a connector on lower-efficiency appliances
II	Negative pressure, condensing	Rarely seen, since these appliances are no longer manufactured
III	Positive pressure, non-condensing	Stainless steel with high-temperature sealant on joints
IV	Positive pressure, condensing	PVC, or CPVC where higher temperature is needed, with sealed joints and 1/4 in per foot pitch back to the appliance

How to Choose Ducting and Ventilation Parts

Check	What to compare
Shape and size	Rectangular or round, and the width, height or diameter of the existing duct
Gauge and material	Galvanized steel gauge, aluminum or flexible duct
Connection	Boot, reducer, cap or coupling that matches both openings
Airflow	CFM and static pressure of the fan or system
Fuel-burning appliance	Vent category and material required by the appliance
Termination	Wall cap, roof vent or tee cap size and finish

Browse related categories: residential air filters and humidifiers.

Frequently Asked Questions

What types of ducting and venting products do you carry?

Nine groups: ductwork and sheet metal, flex duct, grilles, registers and diffusers, dampers, blowers and inline duct fans, fan blades, commercial ventilation, air vents and roof maintenance components, and vent pipes and fittings. Each one is listed with its link in the table above.

What are the common types of ductwork materials?

Galvanized steel or aluminium: durable and mold-resistant, available in round, rectangular, or spiral oval shapes.
Duct board: made from compressed fiberglass, often used in non-load-bearing areas such as between rafters.

Flexible duct is the third common type. Steel is sold by gauge, with 22 gauge about 0.0336 in thick and 30 gauge about 0.0157 in.

Can you explain the different venting categories?

Appliance venting categories describe pressure and condensation, not just vent material. Category I is negative pressure and non-condensing, Category II negative and condensing, Category III positive pressure and non-condensing (stainless steel vent), and Category IV positive pressure and condensing (PVC or CPVC, typical of 90 percent AFUE furnaces). Use the vent type your appliance manual requires. See vent pipes & fittings.

What should I look for in flexible duct hoses?

Check that the duct is listed to UL 181, choose a diameter that matches the boot or collar, and install it fully stretched. Compression and sags cut airflow sharply, so in the Texas A&M study 4 percent compression dropped a 6 in duct from about 110 to about 70 CFM. See flex duct.

Do you provide accessories like clamps and fittings?

Yes, the duct side includes reducers and transition pieces, end caps and vent tee caps, register boots and duct hangers. Seal joints with mastic or UL 181 metal tape rather than cloth tape. See ductwork & sheet metal.

How do I choose between rigid and flexible ducting?

Rigid ductwork (steel or aluminum) is ideal for long, straight runs with minimal airflow loss.
Flexible ducting suits tight spaces or complex configurations, offering ease of installation despite slightly higher airflow resistance.

Use rigid metal for trunks and long runs and flex only for the last connection to an outlet where possible.

How do I seal ductwork?

Use mastic or metal tape that meets UL 181, because cloth-backed duct tape can dry out and fail quickly. Cover seams wider than 1/8 in with fiberglass mesh tape first. Sealing matters, since code-built homes lose around 10 percent of airflow through leaks.