Ventilation & Duct Components
Building a complete grow room ventilation system requires more than just an inline fan and carbon filter -- flexible duct, metal clamps, flanges, reducers, Y-splits, and duct tape are the components that connect these parts into a sealed, efficient exhaust and intake system. Leaks at duct connections reduce system efficiency, allow odor breakthrough around carbon filters, and create pressure imbalances that make climate management harder. Quality ducting components installed correctly produce a ventilation system that performs predictably and maintains its performance over time.
Flexible Duct and Connectors
Flexible aluminum grow room duct (DL Wholesale Terra-Duct, Active Air duct) is available in 4-inch, 6-inch, and 8-inch diameters for the most common inline fan sizes. Flexible duct allows routing around obstacles in the grow room without rigid elbow fittings. Metal clamps (worm-drive hose clamps) create the airtight seal at each connection point between duct and fan, filter, or flange -- never rely on duct tape alone to seal connections where air pressure acts on the joint. Duct flanges and adapters convert between sizes and provide a mounting point for attaching duct runs to fan outlets, filter inlets, and wall penetrations. AC Infinity produces a full line of duct components designed to integrate directly with their Cloudline fan series, including duct connectors, reducers, and Y-splits.
Duct Tape and Sealing
Not all duct tape is created equal for grow room use -- standard household duct tape loses adhesion in the high-humidity environments of active grow rooms and fails at elevated temperatures near ballasts or dehumidifiers. Foil HVAC tape provides a permanent, humidity-resistant seal for duct connections and penetrations. Use metal clamps at fan and filter connections as the primary seal, and foil tape as a secondary seal over the clamped joint. Browse inline fans, carbon filters, and the Ventilation Calculator. Fast shipping.
Ventilation Ducting FAQ
What duct size do I need for my grow room inline fan?
Duct diameter should match your inline fan's inlet and outlet diameter -- most grow room fans are 4-inch, 6-inch, or 8-inch. Reducing duct diameter from the fan's rated size increases static pressure and reduces actual airflow, sometimes significantly. If you need to reduce size to fit a space constraint, do so at the end of the run (closest to the exhaust point) rather than at the fan outlet. For carbon filter connections, the filter's inlet diameter should match the fan or be adapted with a proper reducer -- never neck down a filter-to-fan connection as this is where maximum airflow is needed to pull air through the filter media effectively.
How long can a flexible duct run be without losing too much airflow?
Flexible duct creates friction resistance that reduces actual airflow from the fan's rated output. As a guideline, every 10 feet of flexible duct reduces airflow by approximately 5-10%, and each bend or kink adds additional resistance equivalent to several feet of straight duct. For a typical grow tent setup with a 6-inch fan, a 10-15 foot run with 1-2 gradual bends is manageable with proper fan sizing. Keep runs as short and straight as practical, avoid sharp kinks, and fully extend the duct rather than leaving it compressed -- compressed flexible duct creates significantly more resistance than extended duct. Size your fan with 15-20% extra capacity to compensate for duct resistance.
What is the best way to seal duct connections in a grow room?
The most reliable grow room duct connection uses two layers of sealing: a metal worm-drive clamp as the primary mechanical connection (tightened until the duct flange or fitting is firmly gripped without cutting into the duct material), plus foil HVAC tape wrapped over the clamped joint as a secondary airtight seal. Standard duct tape should not be used in grow rooms -- it loses adhesion in high humidity and at elevated temperatures, and connections sealed with duct tape alone typically fail within a few months. Foil HVAC tape maintains adhesion in humid environments and at temperatures up to 200 degrees F. For carbon filter connections where odor containment is critical, a thorough foil tape seal over the clamp joint is especially important.
