01 / AIRFLOWHVAC
Airflow Calculator
Convert between cubic feet per minute and litres per second.
Enter CFM or L/s to convert.
ENGINEERING KNOWLEDGE PLATFORM
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ENGINEERING / PERSPECTIVE
MECHANICAL · CONSTRUCTION · TECHNOLOGYEST. 2026
BUILT FOR CURIOUS MINDS AND PRACTICAL THINKERS.MECHANICAL ✳ HVAC ✳ PLUMBING ✳ CONSTRUCTION
THE KNOWLEDGE JOURNAL
Learn the ideas.
Understand the work.
Explore explainers, field-informed lessons, and practical references. Search by topic or choose an engineering discipline.
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BEI ENGINEERING TOOLBOX / HVAC
HVAC calculators.
Focused tools.
Practical preliminary calculators for common HVAC and mechanical engineering quantities. Enter your values and review the calculated results.
Explore 5 hvac engineering calculators. Preliminary calculations only; verify design against applicable standards and project requirements.
5 CALCULATORS
02 / DUCT SIZINGHVAC
Duct Sizing Calculator
Estimate required duct cross-sectional area and equivalent round diameter from airflow and target velocity.
Enter airflow and target velocity.
03 / VENTILATIONHVAC
ACH Calculator
Calculate required airflow from room dimensions and air changes per hour.
Enter room dimensions and ACH.
04 / COOLING CAPACITYHVAC
Cooling Capacity Converter
Convert cooling capacity between BTU per hour, refrigeration tons, and kilowatts.
Enter cooling capacity in BTU/hr.
09 / COOLING LOADHVAC
Sensible Cooling Load Estimator
Estimate sensible load from outdoor-air flow and temperature difference plus entered internal sensible gains.
Enter outdoor-air flow, temperature difference, and internal gains.
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Engineering note: These tools provide preliminary calculations for learning and checking. They do not replace project-specific design, code requirements, equipment selection, manufacturer data, or review by a qualified engineer. Duct sizing is based on area continuity only. ACH is not, by itself, a determination of required outdoor ventilation air. Reynolds regime thresholds are indicative for internal pipe flow. Darcy-Weisbach requires an appropriate Darcy friction factor and excludes fittings and minor losses. Pump head requires correctly determined system-head components. The sensible cooling estimator includes only the entered outdoor-air sensible load and internal sensible gains; it excludes envelope transmission, solar gains, latent loads, infiltration, diversity, and other load components, so it is not a complete room cooling-load calculation.
BEI 5.5 / HVAC CALCULATORSReturn to the journal →
EXPLORE BY DISCIPLINE
Knowledge has
many directions.
Choose a field and explore concepts, methods, and lessons that connect engineering theory with practical work.
01Mechanical EngineeringThermodynamics, machinery, power systems↗
02HVAC EngineeringAirflow, cooling loads, ducts and equipment↗
03Plumbing EngineeringWater supply, drainage and sanitary systems↗
04Construction & EstimationQuantity takeoff, costing and site practice↗
05Engineering CareerLicensure, skills and professional growth↗
THE ENGINEER'S TOOLBOX
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↗CHK
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↗Resources will be reviewed and clearly identified by version and intended use.
BEI.
ABOUT THE FOUNDER
Built on curiosity.
Driven by learning.
Benzon Engineering Insights is an independent knowledge platform created to make engineering concepts easier to understand and practical knowledge easier to access.
Founded by CLIFFORD BENZON, RMEE, the platform is intended for engineering students and practicing professionals who believe that learning continues beyond the classroom.
CLIFFORD BENZON, RMEEFOUNDER & ENGINEERING AUTHOR