--- product_id: 531396534 title: "AC Infinity Automatic Duct Fan 4\" Inline Fan." brand: "ac infinity" price: "HK$2156" currency: HKD in_stock: true reviews_count: 13 category: "Ac Infinity" url: https://www.desertcart.hk/products/531396534-ac-infinity-automatic-duct-fan-4-inline-fan store_origin: HK region: Hong Kong --- # 230 CFM airflow Omnidirectional mounting 5-speed PWM EC motor AC Infinity Automatic Duct Fan 4" Inline Fan. **Brand:** ac infinity **Price:** HK$2156 **Availability:** ✅ In Stock ## Summary > 💨 Elevate your airflow game—smart, silent, and unstoppable! ## Quick Answers - **What is this?** AC Infinity Automatic Duct Fan 4" Inline Fan. by ac infinity - **How much does it cost?** HK$2156 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.hk](https://www.desertcart.hk/products/531396534-ac-infinity-automatic-duct-fan-4-inline-fan) ## Best For - ac infinity enthusiasts ## Why This Product - Trusted ac infinity brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Flexible Installation:** Mount in any direction—vertical, horizontal, or diagonal—for ultimate airflow versatility. - • **Effortless Airflow Boost:** Automatically activates with pressure sensing—no manual tweaks needed. - • **Whisper-Quiet Efficiency:** Operates at a low 60 dBA with energy-saving brushless motor technology. - • **Industrial-Grade Durability:** Robust metal build with dual ball bearings designed for long-lasting performance. - • **Precision Ventilation Control:** Five adjustable speeds powered by advanced PWM-controlled EC motor for tailored airflow. ## Overview The AC Infinity Automatic Duct Fan 4" is a high-performance inline ventilation booster designed for both home and industrial HVAC systems. Featuring a smart differential pressure switch, it automatically activates based on airflow changes, eliminating manual adjustments. With five PWM-controlled speeds and omnidirectional mounting, it delivers precise, versatile airflow at 230 CFM while maintaining quiet operation at 60 dBA. Built with durable metal and dual ball bearings, this fan ensures reliable, energy-efficient ventilation in any duct setup. ## Description Product DescriptionAn automatic booster fan designed to improve airflow delivery in longer ductwork for more effective heating or cooling in home or industrial settings. Features a highly intuitive differential pressure switch that senses changes in your ducting to automatically operate its on/off activation. It also allows for mounting in any direction, making it possible to direct airflow vertically, horizontally, or diagonally. The inline duct fan also features five speeds powered by PWM controls that can generate precise airflow levels. This, combined with its flexibility in installation, provides total ventilation control in extended ducting and other difficult-to-reach spaces.Automatic Pressure SensingThe fan pressure switch delivers automatic activation capabilities to boost your heating or cooling on-demand, eliminating the need for manual adjustments. This is achieved by detecting pressure change in your ducting and turning it on whenever your home appliance is on. The smart sensor also allows you to omnidirectionally mount the duct fan for enhanced airflow versatility in existing HVAC systems.Quiet and Energy Efficient DesignThe automatic duct fan features a next-gen EC motor that powers quiet and energy-efficient performance. This innovative motor is controlled with PWM technology to ensure smooth performance while minimizing heat and noise levels. Its mixed flow design gives this vent booster fan a high static pressure rating to enhance airflow in HVAC applications with restricted air movement. This includes industrial settings like manufacturing and processing plants, as well as home residential settings such as bathroom ventilation and central air and heating systems. Review: Fantastic booster fan - It's a great basic duct booster fan. It's a simple design. Great value! The airflow is great with minimal noise. Review: Recommend great product quite - Very good. Not noisy Automatic great. Boosts under power microwave. No more kitchen smells or false smoke alarms ## Features - Inline duct fan for boosting airflow in ducting and vent systems to ensure heating or cooling delivery. - Automatically activates the ventilation fan by detecting pressure change to eliminate manual adjusting. - Differential pressure switch supports mounting in any position to improve directional airflow versatility. - Features five fan speed levels powered by the PWM-controlled EC motor for more precise ventilation. - Duct Size: 4” | Dim: 6.9 x 11.9 x 7.4 in. | Airflow: 230 CFM | Noise: 60 dBA | Bearings: Dual Ball ## Technical Specifications | Specification | Value | |---------------|-------| | Blade Length | 4 inches | | Brand | AC Infinity | | Color | Black | | Electric Fan Design | Blower | | Electric fan design | Blower | | Item Dimensions D x W x H | 9.25"D x 11.88"W x 9.11"H | | Item Weight | 2.27 kg | | Material | Metal | | Power Source | Corded Electric | | Product Dimensions | 9.25"D x 11.88"W x 9.11"H | | Room Type | Bathroom | | Special Features | Pressure Switch | | Style | 10-Inch, Speed Controller | ## Product Details - **Brand:** AC Infinity - **Color:** Black - **Electric fan design:** Blower - **Mounting Type:** Vent - **Power Source:** Corded Electric - **Product Dimensions:** 9.25"D x 11.88"W x 9.11"H - **Recommended Uses For Product:** Cooling, Exhausting - **Room Type:** Bathroom - **Special Feature:** Pressure Switch - **Style:** 10-Inch, Speed Controller ## Images ![AC Infinity Automatic Duct Fan 4" Inline Fan. - Image 1](https://m.media-amazon.com/images/I/51DcPrezDUL.jpg) ![AC Infinity Automatic Duct Fan 4" Inline Fan. - Image 2](https://m.media-amazon.com/images/I/71Rne3p3pgL.jpg) ![AC Infinity Automatic Duct Fan 4" Inline Fan. - Image 3](https://m.media-amazon.com/images/I/61jYMM1cRuL.jpg) ![AC Infinity Automatic Duct Fan 4" Inline Fan. - Image 4](https://m.media-amazon.com/images/I/6168TVhAvFL.jpg) ![AC Infinity Automatic Duct Fan 4" Inline Fan. - Image 5](https://m.media-amazon.com/images/I/71LAz3CXT2L.jpg) ## Customer Reviews ### ⭐⭐⭐⭐⭐ Fantastic booster fan *by R***E on June 29, 2026* It's a great basic duct booster fan. It's a simple design. Great value! The airflow is great with minimal noise. ### ⭐⭐⭐⭐⭐ Recommend great product quite *by P***E on July 4, 2026* Very good. Not noisy Automatic great. Boosts under power microwave. No more kitchen smells or false smoke alarms ### ⭐⭐⭐⭐⭐ Increases dryer efficiency: no error codes from the dryer *by J***D on July 15, 2026* It provides the added venting so that my dryer doesn't give me an error code due to insufficient venting. Increases clothes drying efficiency. It did stop working for a couple of weeks, but has been doing the job for most of the 2 years I have owned it. ## Frequently Bought Together - AC Infinity Automatic Duct Fan 4", Inline Fan with Differential Fan Pressure Switch, Air Vent Booster Fan for Industrial HVAC Ducting Ventilation Exhaust Systems - AC Infinity Duct Adapter, 6” to 4” Ducting Reducer Increaser Cone for Grow Tent Bathroom Kitchen Ventilation Systems - AC Infinity Flexible 4-Inch Aluminum Ducting, Heavy-Duty Four-Layer Protection, 25-Feet Long for Heating Cooling Ventilation and Exhaust --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.hk/products/531396534-ac-infinity-automatic-duct-fan-4-inline-fan](https://www.desertcart.hk/products/531396534-ac-infinity-automatic-duct-fan-4-inline-fan) --- *Product available on Desertcart Hong Kong* *Store origin: HK* *Last updated: 2026-08-14*