Author: longwell

Fan wall array installed in a commercial building air handling unit
By longwell / September 14, 2026 / Fan Engineering Guides

HVAC Fan Wall in Commercial Buildings (Case Study)

A worked example of a fan wall project in a commercial office building...

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Power meter comparing EC fans and AC fans on a test rig
By longwell / September 14, 2026 / Fan Engineering Guides

How Much Energy Do EC Fans Really Save?

Vendors quote 30, 50 or 70 percent. The honest answer depends on how m...

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Spreadsheet calculating EC fan payback for a ventilation upgrade
By longwell / September 14, 2026 / Fan Engineering Guides

EC Fan Payback Period: Real Numbers

Payback is simple arithmetic that people get wrong by leaving items ou...

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Sound level measurement comparing EC fan noise at different speeds
By longwell / September 14, 2026 / Fan Engineering Guides

Noise Reduction with EC Fans (Real dB Tests)

EC fans are often sold as quieter, and at full speed the difference is...

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Smart fans reporting status data to a building management dashboard
By longwell / September 13, 2026 / Fan Engineering Guides

Smart Fans: Monitoring & IoT Control

Modern EC fans report speed, current, temperature and faults. Used pro...

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Backward-curved EC plug fan mounted on a support frame in an AHU
By longwell / September 13, 2026 / Fan Engineering Guides

Backward-Curved EC Plug Fan: The AHU Workhorse

One fan type now dominates air handling units. The combination of a ba...

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Engineer calculating energy savings for a fan upgrade from logged data
By longwell / September 13, 2026 / Fan Engineering Guides

How to Calculate Energy Savings for a Fan Upgrade

A defensible savings figure comes from a week of logged data and four ...

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Grid of small fans beside a single large centrifugal fan for comparison
By longwell / September 13, 2026 / Fan Engineering Guides

Grid of Small Fans vs One Big Fan: Efficiency Truth

Arrays are often sold as more efficient than a single large fan. On pu...

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Fan factory production line assembling centrifugal blowers
By longwell / September 13, 2026 / Fan Engineering Guides

Inside a Fan Factory: From Coil to Finished Blower

A finished blower passes through roughly a dozen processes, and each o...

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Fan test chamber set up for AMCA 210 airflow measurement
By longwell / September 13, 2026 / Fan Engineering Guides

How We Test Fans (AMCA 210/211 Method)

A fan curve only means something when you know how it was produced. Th...

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