Cooling Load Calculator - HVAC Calculator Toolbox

About this calculator This calculator determines the sensible, latent, and total cooling loads for a single A→B process. Enter CFM and elevation, then define the Entering and Leaving air by specifying dry bulb plus one other property (wet bulb, dew point, relative humidity, humidity ratio, enthalpy, or specific volume). All three loads come from the same two state points. Elevation applies the altitude density factor (DF) to all three load factors automatically.

Use when You need the sensible, latent, and total cooling load for an airflow going from one air condition (entering) to another (leaving).

Formula Q = DF × CFM × [1.08·ΔT (sensible) | 0.69·ΔW (latent) | 4.5·Δh (total)]

Variables

CFM Airflow in cubic feet per minuteElevation Site elevation in feet — used to compute the altitude density factor automaticallyEntering / Leaving Dry Bulb Dry bulb temperature (°F) at each stateEntering / Leaving Second Property Your choice of Wet Bulb, Dew Point, Relative Humidity, Humidity Ratio, Enthalpy, or Specific Volume at each stateDF Altitude density factor — applied to all three load factors

Airflow & Location

CFM

Airflow in cubic feet per minute

Elevation (ft)

Site elevation above sea level — leave blank for sea level (DF = 1.0)

Entering Conditions

Dry Bulb (°F)

Dry bulb temperature

Known Property

Wet Bulb (°F)

Leaving Conditions

Dry Bulb (°F)

Dry bulb temperature

Known Property

Wet Bulb (°F)

Process Loads

Enter CFM to view process loads.

Entering Conditions

Dry Bulb

—°F

Wet Bulb

—°F

Dew Point

—°F

Relative Humidity

—%

Humidity Ratio

—gr/lb

Enthalpy

—BTU/lb

Specific Volume

—ft³/lb

Leaving Conditions

Dry Bulb

—°F

Wet Bulb

—°F

Dew Point

—°F

Relative Humidity

—%

Humidity Ratio

—gr/lb

Enthalpy

—BTU/lb

Specific Volume

—ft³/lb

What are sensible, latent, and total cooling loads?

These are three components of one cooling process, not three independent calcs. Sensible cooling load is the portion associated with dry bulb temperature change, calculated as Q = 1.08 × DF × CFM × ΔT. Latent cooling load is the energy required to change the humidity ratio of the air, calculated as Q = 0.69 × DF × CFM × ΔW where ΔW is the humidity ratio difference in grains per pound. Total cooling load is the combined sensible and latent load, calculated as Q = 4.5 × DF × CFM × Δh where Δh is the enthalpy difference in BTU/lb. The constants 1.08, 0.69, and 4.5 are derived from standard sea-level air density (0.075 lb/ft³) and scale by the altitude density factor DF = (1 − 0.00000687 × Alt)^5.256.

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