Custom Air Ducts: Made-to-Order Flexible Ducting from Our USA Factory

Why Custom Ducting?

Standard flexible duct sizes cover most residential and light commercial HVAC applications. But many projects require something the catalog does not offer — a non-standard diameter to match existing ductwork, an unusually long roll to minimize connections on a long run, a higher R-value than standard for extreme climates, or a specialty material for high-temperature or corrosive environments.

As a duct manufacturer — not a distributor — we control the production process from raw material to finished product. This means we can modify any specification without the limitations of a fixed product line. When you order custom air ducts from USFlexDuct, you are ordering directly from the factory floor, not requesting a special order through a supply chain of middlemen.

Our Custom Manufacturing Capabilities

Custom Duct Sizes: 2" to 48"

Our production lines handle inner diameters from 2 inches (for instrument air and small exhaust) to 48 inches (for large commercial air handling and industrial ventilation). Standard diameters follow the industry convention: 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, and 24 inches. See our complete flex duct sizes guide for standard specifications.

For non-standard diameters — metric sizes (e.g., 150mm, 200mm, 315mm for European specifications), intermediate imperial sizes (e.g., 11", 13", 15"), or large diameters above 24" — we manufacture to your exact specification. The wire core pitch, strip width, and forming die are adjusted to produce the precise inner diameter you need.

Custom lengths are one of our most common requests. Standard rolls are 25 feet, but many projects benefit from longer rolls (fewer connections = fewer potential leak points = faster installation). We produce 50-foot and 100-foot rolls for large commercial projects, and shorter 10-foot and 15-foot rolls for retrofits where space is limited and long rolls are unwieldy.

Custom Insulation Options

Standard insulated flex duct comes in three R-values: R4.2 (1" fiberglass), R6 (1.5" fiberglass), and R8 (2" fiberglass). For projects requiring higher thermal performance — extreme climate zones, data centers with precise temperature control, or process ducting with high-temperature differentials — we manufacture R10 and R12 insulated flex duct.

Custom insulation configurations include high-density fiberglass (24 kg/m3 vs standard 16 kg/m3) for enhanced acoustic performance, closed-cell foam insulation for moisture-critical applications (crawl spaces, pool dehumidification), and double-layer insulation (fiberglass inner + reflective foil outer) for maximum thermal performance. See our R6 vs R8 comparison and duct insulation guide for thermal performance data.

Specialty Materials

Beyond standard aluminum and polyester, we manufacture flexible duct in specialty materials for demanding industrial applications:

Stainless steel (304/316) — for corrosive environments (coastal installations, chemical processing, food service exhaust). 316L stainless resists chloride corrosion and is required in marine and coastal HVAC applications.

Silicone-coated fiberglass — rated to 500°F continuous (250°C) for high-temperature exhaust, industrial oven ventilation, and engine test cell ducting. See our silicone duct hose product.

Anti-static PU (polyurethane) — with embedded copper ground wire for combustible dust collection systems. Meets NFPA 652 and 664 requirements for static dissipation. See our anti-static duct guide.

PTFE-lined — for aggressive chemical fume extraction (acids, caustics, solvents). PTFE is chemically inert and maintains flexibility from -100°F to 500°F.

OEM & Private Label Manufacturing

We provide OEM manufacturing and private-label packaging for HVAC distributors, retailers, and brands who want custom duct products under their own branding. Our OEM capabilities include custom packaging (branded poly bags, cartons, or crates), custom labeling (your logo, part numbers, and specifications printed on the duct jacket and packaging), and custom product configurations (your specifications, your SKUs, your documentation).

OEM minimum order quantities are typically 2,000-5,000 pieces per SKU depending on the product type and customization level. Lead time for OEM orders is 30-45 days from specification approval to shipment. We handle all export logistics from our Dongyang facility to your US warehouse or directly to your distribution centers.

How to Order Custom Ducts

Step 1: Contact us with your specifications. Tell us the diameter, length, insulation R-value, material, temperature rating, and quantity you need. If you are not sure about the specifications, our engineering team can recommend the right configuration based on your application.

Step 2: We provide a quote within 24 hours (standard customizations) or 48 hours (specialty materials and non-standard sizes). The quote includes per-unit pricing, tooling costs (if applicable), lead time, and shipping estimate.

Step 3: Approve and produce. Once you approve the quote, we schedule production. For standard customizations, production begins within 1-2 business days. For non-standard specifications, we may produce a sample for your approval before running the full order.

Step 4: Ship from our warehouse. Standard orders ship from our Brookshire, TX warehouse. Large or specialty orders may ship directly from our production facility. We provide tracking information for all shipments.

Lead Times & Pricing

Pricing for custom ducts depends on diameter, material, insulation, and quantity. As a general guideline, custom specifications add 15-40% to standard product pricing. Volume discounts apply to orders above 1,000 linear feet. Contact our sales team for a detailed quote on your specific requirements.