Why Trust This Guide?

Part 1: Decoding the Terminology – What Are You Really Buying?

• Duct Fan / Inline Duct Fan:​ This is the broad, technical category. It refers to any fan unit designed to be installed withina section of ducting, actively boosting airflow along the duct run. Both "mixed flow" and "centrifugal" types fall under this umbrella.
• Inline Fan:​ Often used synonymously with Duct Fan, but sometimes specifically implies an axial-flow design. However, in professional contexts like ours, an "Inline Fan" is engineered for ducted systems.
• Exhaust Fan:​ This describes the function(removing air) rather than the installation type. A wall-mounted bathroom fan is an exhaust fan, but not a duct fan. Our duct fans excel as powerful, quiet exhaust solutions when integrated into ductwork.

Part 2: The Hongguan Advantage – Engineering Precision in Every Detail

Figure 1: Official Performance Parameters of Hongguan HDD-100/125P Inline Duct Fan. This table provides verified data on power consumption, airflow (up to 284 m³/h), pressure generation (up to 159 Pa), and critically, sound levels as low as 22 dB(A) at 3 meters.

• Energy Intelligence:​ The 220V model uses only 33W at high speed to deliver 284 m³/h. This high efficiency is a result of our optimized mixed-flow impeller design.
• The Silence Benchmark:​ At 22 dB(A) on low speed, it's quieter than a whisper. This is achieved through precision-balanced blades and sound-absorbing housing materials.
• Real Power:​ 159 Pa of static pressure means it can push air through long ducts, filters, or louvers without significant performance drop.

Figure 2: Performance Curve (Airflow vs. Static Pressure) for the HDD-100/125P. The "HS" (High Speed) and "LS" (Low Speed) curves show the fan’s operating range. To use this, calculate the pressure drop in your duct system at your desired airflow; the point where that pressure drop intersects our curve is your operating point.

Figure 3: Detailed Installation Dimension Drawing (in mm) for the HDD-100/125P. This drawing provides all critical mounting dimensions, flange details, and clearances needed for a perfect fit into your duct system.

Part 3: How Hongguan Solved a Client’s Critical Ventilation Problem

• High-Pressure Capability:​ The centrifugal design generates significantly higher pressure than axial fans, ideal for pushing air through restricted paths.
• Thermal Protection Built-in:​ Our fans came with built-in thermal protection, ensuring reliability in the very hot environment they were solving.

Part 4: Your 5-Step Decision Framework: Choosing the Right Hongguan Fan

1. Define Your Goal:​ Is it for exhaust​ (removing air), supply​ (bringing air in), or recirculation?
2. Calculate Your Airflow Need:​ Estimate room volume and required air changes per hour (ACH). We can help with this.
3. Assess System Resistance:​ Long ducts, filters, grilles, and bends create static pressure. This is the most critical and often overlooked step.
   • High Resistance (e.g., >100 Pa with filters/long ducts):Choose our Centrifugal (HEE Series) Duct Fans.
   • Medium Resistance (e.g., 50-150 Pa in typical ducts):Choose our Mixed Flow (HDD/HF Series) Duct Fans​ – the perfect balance of airflow and pressure.
4. Prioritize Noise Level:​ For offices, studios, or homes, our Silent (HDD) Series​ is mandatory. For industrial settings, our standard models offer robust performance.
5. Consider Energy & Control:​ For 24/7 operation, our ECOWATT (EC Motor) Series​ provides dramatic lifetime energy savings and speed control compatibility.

Conclusion: It’s More Than a Fan, It’s a System Solution