Specialized Engineering Suite

HVAC & Airflow Calculators

BTU sizing, heating & cooling loads, AC tonnage, duct sizing, CFM airflow, and ventilation calculators.

HVAC & Mechanical Engineering Suite

Equal Friction Duct Sizing & CFM Airflow

Size supply ducts, return air trunks, and branch runs using Huebscher rectangular conversion and standard friction loss rates (0.05 to 0.1 in. wg/100 ft).

Calculate HVAC Duct Sizing & Branch CFM

Manual J Thermal Load & AC Tonnage

Estimate whole-house or room heating and cooling loads (BTU/hr) and size residential split systems and heat pumps across climate zones 1 through 7.

Calculate Heating & Cooling BTU Load & Tonnage

Available Calculators in Suite

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HVAC BTU Heating & Cooling Load Calculator

Calculate heating and cooling BTU/hr loads, recommended AC tonnage (1.5 to 5 tons), mini-split sizing, and sensible/latent heat gains across climate zones.

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HVAC Duct Sizing & CFM Airflow Calculator

Calculate round duct diameters, rectangular equivalent dimensions, air velocity (FPM), friction loss, and room branch distribution for HVAC systems.

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