VIVOSUN 4-inch Inline Fan R4 — 190 CFM Quiet, Energy-Efficient, Stepless Speed Controller

The VIVOSUN R4 4" Inline Fan delivers up to 190 CFM of quiet, energy-efficient air movement for small grow tents, bathrooms, basements and workshops.

This compact inline duct fan combines axial and centrifugal design features to move a steady stream of air while keeping noise and power use low. Built from reinforced plastic, the R4 is designed for continuous indoor use where reliable airflow, adjustable speed and easy installation matter. It ships with a removable mounting bracket, locking duct ends and a stepless speed controller so you can tailor performance to different rooms and setups.

How much airflow and power does the R4 provide?

The R4 produces up to 190 cubic feet per minute (CFM) at a fan speed of 2300 RPM, giving effective circulation for small to medium ventilation needs. Its blended fan design balances volume and static pressure better than a basic axial fan.

• Maximum rated airflow: 190 CFM
• Top fan speed: 2300 RPM
• Motor-driven blower combines axial and centrifugal elements
• Reinforced plastic housing for steady performance

Will the fan be noisy in a home or grow space?

The R4 is engineered for reduced acoustic output: smooth-blade rotation and balanced construction keep operational noise under about 30 dB in typical conditions. That level is low enough to be unobtrusive near work areas, bedrooms or small grow tents.

• Typical noise level: below 30 dB
• Durable fan blades minimize vibration and rattle
• Suitable for noise-sensitive rooms like bathrooms or basements
• Quieter than many same-size inline fans under similar load

How easy is the R4 to install and control?

Installation is straightforward: the fan is compact and lightweight, with removable duct ends and locking tabs to secure ducting. A mounting bracket indicates airflow direction and the included inline stepless speed controller lets you dial the output to the exact airflow you need.

• Compact footprint fits tight spaces and small tents
• Installation bracket shows correct airflow orientation
• Removable duct ends with locking tabs for secure connections
• Inline stepless speed controller for precise adjustment

What indoor uses are best suited to this fan?

The VIVOSUN R4 is made for indoor ventilation tasks where space is limited but consistent airflow is required. It works well in horticulture setups, moisture-prone rooms, small workshops and ventilation runs where you need to move air quietly and efficiently.

• Grow tents and small grow rooms for air exchange and circulation
• Bathroom ventilation to help reduce humidity buildup
• Basements and laundry areas to combat stagnant air
• 3D printing or small workshop exhaust to manage heat and dust

Who is this for? The VIVOSUN R4 4" Inline Fan is intended for hobby growers, apartment dwellers, small workshop operators and homeowners needing a compact, quiet inline fan. If you want an affordable, easy-to-install duct fan with adjustable speed and low noise for confined indoor spaces, the R4 is a practical choice. It’s not a heavy industrial blower, but it offers reliable continuous ventilation performance where space, sound and flexibility matter.