Sound Insulated Box Fan (VSIF)
Under-ceiling silent exhaust fan with grilled inlet and ducted exhaust — 200–1,500 CFM.
About the Sound Insulated Box Fan (VSIF)
A silent ceiling exhaust fan replaces the noisy bath-fan-on-the-wall with something that belongs above the ceiling tile. The impeller is wrapped in 25 mm acoustic insulation and double-skin sheet metal, so the only sound that reaches the occupant is the gentle inrush at the grille. Grilled-inlet, ducted-exhaust configuration lets one unit serve multiple toilets, kitchenettes, lab benches or smoke booths through a manifold duct.
Engineering Advantages
Acoustic insulation drops breakout noise 8–12 dBA versus an uninsulated fan
One unit can manifold-serve multiple grilles via the discharge duct
Forward-curved impeller delivers high airflow at low static
Slim profile fits into standard false-ceiling cavities (≥ 400 mm)
Key Features
- Mounts under false ceiling
- Grilled inlet / ducted exhaust
- Very low sound / low power consumption
Construction & Materials
- Double-skin sheet-metal cabinet with 25 mm acoustic-thermal liner
- Forward-curved impeller — high airflow at moderate static
- External-rotor or direct-drive motor with sealed bearings
- Inlet grille and rectangular discharge spigot included
- Hinged or removable access panel for impeller cleaning
How to Choose the Right Variant
- 1Pick airflow based on number of grilles × CFM/grille (typically 75 CFM per WC, 100 CFM per shower)
- 2Add static pressure for the manifold duct + grilles
- 3For cafeterias / smoke rooms, size for 10–12 air changes per hour minimum
Installation Notes
- Hang from threaded rod with anti-vibration isolators
- Connect inlet to grille via short duct or directly to a plenum box
- Provide service access via the ceiling tile — minimum 600 × 600 mm clear
- Wire through a service-isolator above the ceiling
Maintenance Schedule
- Wash inlet grille every 3 months
- Open and clean impeller annually
- Inspect duct connections at the spigot annually
Industries Served
Standards & Compliance
- Acoustic liner per IS 8183 mineral wool
- IP 44 motor protection per IEC 60529
Frequently Asked Questions
Does the insulation reduce airflow?
No — the insulation is on the cabinet walls, outside the air path. Airflow through the impeller is unchanged.
Can it replace a noisy bath fan?
Yes — most hotel and hospital projects swap noisy direct-mount bath fans for a single ceiling-mounted unit serving multiple rooms via a small manifold duct.
Need help selecting the right fan?
Our engineers will help you size the sound insulated box fan (vsif) to your exact application — capacity, static pressure, and installation constraints.
