Fan Efficiency

Fan efficiency should be judged wire-to-air — from electrical input to useful air power — not from motor nameplate alone. Articles cover FEI metrics, part-load behaviour, annual energy calculation and the design factors separating premium EC platforms from commodity fans.

Axial fan blade pitch and angle of attack shown on a hub
By longwell / September 10, 2026 / Fan Engineering Guides

Fan Blade Pitch & Angle of Attack Explained

Pitch is the single strongest lever on axial fan performance. Increase...

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Airfoil impellers with aerofoil section blades in a centrifugal fan
By longwell / September 10, 2026 / Fan Engineering Guides

Why Airfoil Impellers Are the Most Efficient

Airfoil blades reach the highest static efficiency of any centrifugal ...

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Volute cutoff clearance shown between the scroll tongue and the wheel
By longwell / September 10, 2026 / Fan Engineering Guides

Volute / Scroll Housing & Cutoff Design

The scroll does half the work in a centrifugal fan, and the cut-off de...

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Fan inlet cone and venturi ring guiding air into an impeller
By longwell / September 10, 2026 / Fan Engineering Guides

Inlet Cone & Venturi: Small Part, Big Efficiency

The inlet cone is a cheap pressing that decides how cleanly air enters...

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Specific speed chart mapping fan types against duty ranges
By longwell / September 9, 2026 / Fan Engineering Guides

Specific Speed: How Engineers Pick a Fan Type

Specific speed collapses airflow, pressure and rotational speed into o...

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Sound power measurement of a fan in an acoustic test chamber
By longwell / September 9, 2026 / Fan Engineering Guides

Sound Power vs Sound Pressure (dB Deep Dive)

Sound power belongs to the fan. Sound pressure belongs to the room. Co...

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Axial fan tip clearance between blade tips and the venturi ring
By longwell / September 9, 2026 / Fan Engineering Guides

Tip Clearance & Leakage in Fans

Air escaping past the blade tips is pure loss, and the gap causing it ...

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Reynolds number comparison between a small and a large fan impeller
By longwell / September 9, 2026 / Fan Engineering Guides

Reynolds Number: Scaling Fans Small to Large

Two geometrically identical fans of different sizes do not perform ide...

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Fan efficiency grade and FEI values compared on a performance curve
By longwell / September 9, 2026 / Fan Engineering Guides

Fan Efficiency Grade (FEG/FEI) Deep Dive

FEG rated the fan. FEI rates the selection. That single difference exp...

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How-to-Seal-Ducts---Cut-Leakag
By longwell / August 24, 2026 / Fan Engineering Guides

How to Seal Ducts & Cut Leakage

Duct sealing begins by identifying function, not by choosing tape or m...

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