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Free HVAC Calculators & Engineering Tools
60+ professional HVAC calculators for sizing, converting and diagnosing air conditioning, refrigeration, heating, ventilation and electrical systems. Free, instant, no signup.
Air Conditioning Tools
Size, convert and cost air conditioning systems with calculators for room sizing, BTU/kW conversion, running costs, installation costs and efficiency ratios.
Refrigeration Tools
Calculate superheat, subcooling, refrigerant charges, pipe sizes and GWP for refrigeration and air conditioning systems.
Airflow & Ventilation Tools
Size ductwork, calculate airflow, air changes per hour, pressure drops and fan static pressure for ventilation systems.
Heating & Hydronic Tools
Size boilers, calculate heat loss, water flow rates, pump head, pipe sizes, expansion vessels and heat exchangers for heating systems.
Commercial HVAC Tools
Calculate chiller capacity, cooling loads, AHU airflow, FCU sizing, VRF diversity, psychrometrics and dew point for commercial buildings.
Gas Tools
Calculate gas rates, pipe sizes, pressure drops and convert between gas flow and heat input for Gas Safe engineers.
Electrical Tools
Convert kW to amps, calculate voltage drop, power factor and kVA for HVAC electrical load sizing and cable selection.
Quick Converters
Instantly convert between common HVAC units: pressure, temperature, capacity, airflow, flow rate and length.
Professional HVAC Calculators Online
HVACX offers a comprehensive suite of free online HVAC calculators designed for engineers, installers, contractors and facility managers. Our tools cover every aspect of HVAC system design, installation, commissioning and maintenance — from air conditioning sizing and refrigerant charging to duct sizing, boiler selection and electrical load calculations.
All calculators use industry-standard formulas and are regularly updated to reflect current best practices and regulations. Whether you're sizing a split system for a residential property, calculating superheat and subcooling for a refrigeration system, or determining the cooling load for a commercial building, our tools provide accurate, instant results.
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