Live calculators
Start with the calculators already available for this section, then open the related guides when you need more context.
Dew Point Calculator
Dew-point temperature from dry-bulb and relative humidity (Magnus vapor pressure, liquid water).
Duct Size & Velocity Calculator
Cross-section from airflow and target velocity — round diameter or rectangular second side.
Psychrometric Calculator
Humidity ratio and air enthalpy from dry-bulb, RH, and barometric pressure — quick moist-air check.
Sensible Heat Calculator
Sensible heat rate from mass flow or dry-air volume flow, cp, and temperature difference.
Air Changes Calculator
Browser-based preliminary check for Air Changes Calculator — fast estimates, not code or stamped design output.
Duct Friction Loss Calculator
Browser-based preliminary check for Duct Friction Loss Calculator — fast estimates, not code or stamped design output.
Latent Heat Calculator
Browser-based preliminary check for Latent Heat Calculator — fast estimates, not code or stamped design output.
Mixing Air Calculator
Browser-based preliminary check for Mixing Air Calculator — fast estimates, not code or stamped design output.
Total Heat Calculator
Browser-based preliminary check for Total Heat Calculator — fast estimates, not code or stamped design output.
Coil Load Estimator
Browser-based preliminary check for Coil Load Estimator — fast estimates, not code or stamped design output.
Delta T Temperature Converter
Browser-based preliminary check for Delta T Temperature Converter — fast estimates, not code or stamped design output.
Heat Gain Calculator
Browser-based preliminary check for Heat Gain Calculator — fast estimates, not code or stamped design output.
Heat Loss Calculator
Browser-based preliminary check for Heat Loss Calculator — fast estimates, not code or stamped design output.
Humidity Ratio Calculator
Browser-based preliminary check for Humidity Ratio Calculator — fast estimates, not code or stamped design output.
Insulation Heat Transfer Calculator
Browser-based preliminary check for Insulation Heat Transfer Calculator — fast estimates, not code or stamped design output.
Relative Humidity Converter
Browser-based preliminary check for Relative Humidity Converter — fast estimates, not code or stamped design output.
Room Cooling Load Estimator
Browser-based preliminary check for Room Cooling Load Estimator — fast estimates, not code or stamped design output.
U Value Helper
Browser-based preliminary check for U Value Helper — fast estimates, not code or stamped design output.
How teams use this section
Use these workflows to choose the right calculator path before moving into deeper analysis or formal design checks.
Psychrometrics and mixed air
Track dry bulb, humidity, and enthalpy trends when outdoor air, return air, or coils change the state point.
Sensible vs latent loads
Split heat into components that move temperature versus moisture so coil and airflow reasoning stays honest.
Duct velocity and sizing checks
Relate airflow, area, and velocity targets for early distribution layouts before detailed loss networks.
Heat loss and ventilation air changes
Connect envelope thinking to ACH targets when scoping equipment and outdoor air requirements.
Guides for this section
Published guides help explain assumptions, formulas, and the next step after a quick calculator result.
Use this guide for quick condensation-risk screening where you need explicit equations and assumptions, not a black-box psychrometric app.
Primary tool: Dew Point Calculator
Use this guide when you need fast moist-air reasoning for ventilation, mixed air, or coil conversations before opening a full psychrometric chart workflow.
Primary tool: Psychrometric Calculator
Use this guide for first-pass duct sizing when you want a fast area estimate before moving into detailed pressure-loss and noise calculations.
Primary tool: Duct Size & Velocity Calculator
Thermal & HVAC FAQ
Why emphasize psychrometrics early?
Many HVAC mistakes are state-point mistakes, not arithmetic mistakes. Psychrometrics is the shared language for coils, ventilation, and comfort outcomes.
Are these tools suitable for refrigerant circuit design?
They target air-side and load-side quick checks. Refrigerant charge, oil return, and detailed equipment selections still require manufacturer data and applicable standards.
What assumptions should I always document?
Outdoor design conditions, indoor setpoints, infiltration or ventilation basis, and whether loads are peak or annual estimates. Those assumptions dominate whether two engineers agree.