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Equipment sizing and whole-building load work: Manual J style block loads, BTU sizing, envelope conduction and infiltration…
Sizing round and rectangular ducts, computing friction loss and available static pressure, and verifying duct leakage the way…
Airflow requirements per room and per ton, fan law scaling, air change rates and code-required outdoor air ventilation rates.
The moist-air property math behind every coil, dehumidifier and cooling tower: dew point, wet bulb, relative humidity, humidity…
Splitting a cooling load into sensible and latent parts, computing SHR, and sizing dehumidification and condensate handling…
Field calculations technicians run on every service call: superheat, subcooling, target superheat, temperature split, charge…
Converting between SEER, EER, COP and kW/ton, and turning those ratings into real dollars: run cost, upgrade savings, balance…
Water-side heating design: flow rate and pump head, radiant floor loop layout, baseboard and radiator output, and boiler sizing.
Most used in hvac, refrigeration & building science
- Manual J Heating & Cooling Load CalculatorACCA Manual J 8th ed. (block load)This calculator runs a whole-house block load in the shape ACCA Manual J uses: conduction through each envelope assembly…
- Air Conditioner BTU & Tonnage CalculatorAHAM / ENERGY STAR room AC sizing methodEnter the room's floor area and this calculator returns the cooling capacity it needs in BTU per hour and in tons, using the…
- Furnace Size (BTU Input) CalculatorACCA Manual S equipment selectionA furnace is sold by its input rating and it heats your house with its output . This calculator converts the design heat loss…
- R-Value to U-Value Converter CalculatorASHRAE Fundamentals thermal resistance conventionsR-value and U-factor are reciprocals of one another, but they are quoted in different units on either side of the Atlantic and…
- Duct Size Calculator (Equal Friction & Velocity Method)ASHRAE / ACCA Manual D friction equationEnter the airflow a duct has to carry and the friction rate your design allows, and this calculator returns the round diameter…
- Available Static Pressure & Friction Rate CalculatorACCA Manual D friction rate procedureA blower produces a fixed amount of static pressure at its design airflow, and the filter, coil, humidifier, grilles and…
- Room CFM Requirement CalculatorACCA Manual D room airflowThe airflow a room needs follows from one equation: sensible load divided by 1.08 times the temperature difference between the…
- CFM per Ton CalculatorAHRI 210/240 rated airflow basisCFM per ton is the field measurement that tells you whether a cooling system is moving enough air to reach its rated capacity…
- Air Changes Per Hour (ACH) CalculatorASHRAE 62.1 / 62.2 ventilationAir changes per hour is airflow expressed as multiples of the room's own volume: 6 ACH means the fan moves six times the room's…
- Dew Point Calculator (from Temperature & RH)Magnus-Tetens with WMO coefficientsDew point is the temperature at which the air you are standing in becomes saturated, and it is the number that decides whether…
- Wet Bulb Temperature CalculatorASHRAE Handbook—Fundamentals, Ch. 1 (adiabatic saturation)Enter a dry-bulb temperature and either the relative humidity or the dew point, and this calculator returns the thermodynamic…
- Relative Humidity CalculatorASHRAE Handbook—Fundamentals, Ch. 1 (Hyland–Wexler)Enter a dry-bulb and wet-bulb reading from a sling psychrometer or a digital hygrometer and this calculator returns relative…