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Enthalpy Of Air Calculator

Work out enthalpy of air instantly with clear inputs, formula shown and shareable results.

About Enthalpy Of Air Calculator

Enthalpy of moist air is measured per pound of dry air and splits cleanly in two: the sensible term 0.24 x T for the air itself, and the latent term W x (1061 + 0.444 T) for the water vapour it carries. Coil loads are calculated on enthalpy difference because it captures both temperature and moisture change at once.

Formula

Moist air enthalpy

h = 0.24 T + W (1061 + 0.444 T)

W
Humidity ratio, lb water per lb dry air
T
Dry bulb temperature, °F

Worked example

With the default values below, Enthalpy Of Air Calculator returns Total enthalpy of 28.161. Change any input above and every figure here is recalculated in your browser.

Inputs used

Dry bulb temperatureminimum -20 °F
75 °F
Humidity ratiominimum 1 grains/lb
65 grains/lb

Results

Total enthalpy
28.161 BTU/lb dry air
Sensible component
18.000 BTU/lb
Latent component
10.161 BTU/lb
Latent share of enthalpy
36.1% %

Step by step

  1. 1Values used
  2. 2Moist air enthalpy
  3. 3Total enthalpy= 28.161 BTU/lb dry air
  4. 4Sensible component= 18.000 BTU/lb
  5. 5Latent component= 10.161 BTU/lb
  6. 6Latent share of enthalpy= 36.1 %

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Enthalpy Of Air figure worked out?

h = 0.24 T + W (1061 + 0.444 T). Enthalpy of moist air is measured per pound of dry air and splits cleanly in two: the sensible term 0.24 x T for the air itself, and the latent term W x (1061 + 0.444 T) for the water vapour it carries.

Why use enthalpy instead of temperature for coil loads?

A cooling coil removes both heat and moisture. Total capacity is 4.5 x CFM x Δh, which counts the latent work that a temperature-only calculation misses entirely.

What values do I need to enter?

This calculator takes 2 inputs: Dry bulb temperature, Humidity ratio. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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Enthalpy Of Air Calculator – Calculate Total enthalpy