Resource Center

Fan Engineering Resources

Calculators, buyers' guides, cross-reference tables, application cases and downloads for engineers who specify axial, centrifugal, cross-flow and duct fans. Everything here is written by LONGWELL's application team and free to use.

Calculators & Tools

Size airflow, convert units, apply the fan laws, derate for altitude, check motor amps and bearing life.

💨CFM Calculator (Air Changes per Hour)Airflow (CFM / m³/h) a room needs by air changes per hour — 60+ space types.🔥Heat Load & Enclosure Cooling Airflow CalculatorCFM / m³/h to remove a heat load (W or kW) at an allowed temperature rise — cabinets, racks, inverters.❄️AC Size & Cooling Load Calculator (BTU / Tons / kW)Quick cooling load for a room or small building from area, climate, sun, occupants and equipment — and the supply airflow it implies.🍳Range Hood & Kitchen Exhaust CFM CalculatorRange hood and commercial kitchen hood exhaust airflow by hood length, cooking duty and hood type — plus make-up air.🏠Whole House Fan Sizing & Attic Fan CalculatorCFM for a whole-house fan (by climate and air changes) and for attic exhaust (by attic area), with vent-opening and window-opening checks.🚪Air Curtain Sizing CalculatorDischarge velocity, airflow and power for an air curtain by door height, width, wind and temperature difference.🪚Dust Collection CFM & Duct Velocity CalculatorCFM per machine, duct size for transport velocity, static pressure of the run and collector size for a workshop.🌱Grow Tent Fan Size Calculator (CFM & Carbon Filter)Inline exhaust fan CFM for a grow tent or grow room, with carbon-filter, duct, light-heat and CO₂ adjustments.

See all 30 calculators →

Buyers' Guides

Long-form selection guides for specific applications and brand replacements.

Engineering Buyers' Guides 2026Index of all guides
AC to EC Retrofit ROI GuideWhen an EC upgrade pays back
Gas Boiler & Condensing Heater Blower SelectionPremix and combustion blowers
ebm-papst R3G Alternative GuideDrop-in EC centrifugal alternatives
Nicotra Alternative GuideForward/backward-curved equivalents

Cross-Reference

Match an existing fan part number to a Longwell equivalent.

Cross Reference GuideHow to cross a fan by size, airflow, pressure and motor
EC Fan Cross-Reference Tableebm-papst, Ziehl-Abegg, Nicotra, Rosenberg → Longwell

Applications & Cases

Where our fans run and what they were chosen for.

Use CasesBy application: HVAC, refrigeration, data center, agriculture…
ProjectsReference installations
SolutionsData center, heat pump, BESS, cold chain, fan grids
IndustriesAir conditioning, refrigeration, heating, ventilation, drive technology