HVAC Calculators
Professional HVAC engineering tools for duct sizing, cooling loads, ventilation, and system design per ASHRAE standards.
Most used in HVAC
Duct Sizer ProWorld-class duct sizing with visualization, SMACNA compliance, noise criteriaDuct Size CalculatorSize round and rectangular ducts using velocity or equal friction methodTR to CFM CalculatorConvert cooling tonnage to airflow rateBTU / AC Sizing CalculatorFind the right AC size for a room — BTU/hr, tons & kW from area, climate, sun, insulation & occupancyCHW Pipe Size CalculatorSize chilled water pipes using ASHRAE limits (≤2″: 4 ft/s, >2″: 4 ft/100ft). US & Metric modes with velocity and head loss.Cooling & Heat Load CalculatorMulti-zone cooling & heating load (ASHRAE CLTD) — sensible/latent, TR, kW, SHR, supply CFM with whole-building rollup & diversityRefrigeration Pipe SizerSize copper suction, liquid & discharge lines — velocity, pressure drop & ΔT penalty for R410A, R32, R134a, R404A, R22 & R407C with oil-return checks
All 40 HVAC calculators
Duct Sizer ProWorld-class duct sizing with visualization, SMACNA compliance, noise criteriaDuct Size CalculatorSize round and rectangular ducts using velocity or equal friction methodTR to CFM CalculatorConvert cooling tonnage to airflow rateBTU / AC Sizing CalculatorFind the right AC size for a room — BTU/hr, tons & kW from area, climate, sun, insulation & occupancyCHW Pipe Size CalculatorSize chilled water pipes using ASHRAE limits (≤2″: 4 ft/s, >2″: 4 ft/100ft). US & Metric modes with velocity and head loss.Cooling & Heat Load CalculatorMulti-zone cooling & heating load (ASHRAE CLTD) — sensible/latent, TR, kW, SHR, supply CFM with whole-building rollup & diversityFresh Air ACH CalculatorCalculate fresh air requirements based on air changes per hourAC Tonnage CalculatorFind what size AC you need in tons & BTU from room area, climate, insulation & sun — with quick estimate and detailed load modesDew Point CalculatorCalculate dew point & condensation risk from temperature and RH or wet bulb — with humidity ratio, enthalpy & altitude correctionRoom Heat Load CalculatorEstimate room cooling/heating loadHVAC E20 Heat LoadDetailed heat load calculation per E20 methodAirflow Unit ConverterConvert CFM, CMH, L/s and other airflow unitsDuct Friction CalculatorCalculate duct friction loss and velocityFan Static PressureCalculate fan static pressure requirementsAHU Fan Shaft PowerCalculate AHU fan motor powerAC Condensate DrainSize AC condensate drain pipesAC Condensate Drain ProCondensate flow (latent or rule-of-thumb), IMC pipe size, gravity capacity check, P-trap depth, water recovery & condensate-pump sizingCooling Coil SelectionSelect cooling coils based on loadPsychrometric CalculatorCalculate air properties and psychrometric processesVAV Box SizingSize variable air volume boxesKitchen Hood CFMCalculate kitchen exhaust hood airflowSmoke Exhaust CalculatorCalculate smoke exhaust requirements per NFPA 92Chiller TonnageCalculate chiller capacity requirementsCooling Tower CalculatorSize cooling towers and calculate makeup waterChilled Water Pipe CalculatorCalculate pipe size, velocity, friction factor, head loss, elbow loss, and pipe + fluid weightRefrigeration Pipe SizerSize copper suction, liquid & discharge lines — velocity, pressure drop & ΔT penalty for R410A, R32, R134a, R404A, R22 & R407C with oil-return checksBoiler Feed Pump CalculatorSize boiler feed water pumps — flow (m³/hr, GPM), total head & motor kW/HP from boiler capacity & pressure with IEC motor selectionDuct Weight CalculatorSheet metal area, SMACNA gauge and weight for rectangular & round ductPipe Insulation ThicknessASHRAE 90.1 minimum thickness plus chilled-water condensation checkCold Room Load CalculatorCold storage and freezer refrigeration load in kW / TRA2L Refrigerant Charge LimitMax R-32 / R-454B charge or minimum room area (IEC 60335-2-40)Refrigerant PT ChartSaturation pressure-temperature chart for R410A, R32, R22, R134a and moreLMTD & Heat ExchangerLog mean temperature difference, heat duty and heat exchanger areaDiffuser & Grille SizingCeiling diffuser neck size and grille size from airflow and noise levelAC Running CostAir conditioner kWh and electricity cost per day, month and yearFan Laws CalculatorNew airflow, pressure and power when fan speed changesCar Park VentilationBasement parking exhaust by 6/10 ACH and ASHRAE 62.1, with jet fansSuperheat & Subcooling CalculatorSuperheat, subcooling, target superheat and charge check for R410A, R454B, R32 and moreHeat Pump Size CalculatorHeat pump size in tons or kW from heat loss and climate, with balance point and backup heatDuct System Design CalculatorSize a full duct network: index run, fan ESP, balancing and sheet metal BOQ
Nothing in HVAC matches that. The search at the top covers all 125 calculators.
Professional HVAC Engineering Tools
Our HVAC calculators help engineers design efficient heating, ventilation, and air conditioning systems. All calculations follow ASHRAE handbook guidelines and industry best practices.
Duct Sizing
Size supply and return ducts using velocity method or equal friction method. Calculate round, rectangular, and flat oval duct dimensions with proper aspect ratios.
Cooling Load Calculations
Estimate room and building cooling loads using simplified methods or detailed E20 calculations. Convert between TR, BTU, and kW.
Ventilation Design
Calculate fresh air requirements based on occupancy, air changes per hour, and ASHRAE 62.1 standards. Design kitchen exhaust and smoke control systems.