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Calculation Machine

Latent Heat Load Calculator

Moisture removal load from airflow and grain difference.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Latent load
20,400 BTU/h
In tons
1.7
Water removed
19.4 pints/hour
In kW
5.98

Quick answer

Latent load equals 0.68 times CFM times the grains of moisture removed per pound of air.

The formula

BTU/h = 0.68 x CFM x Δgrains

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Airflow1200 CFM
  • Grain difference25 gr/lb

Result

  • Latent load20,400 BTU/h
  • In tons1.7
  • Water removed19.4 pints/hour
  • In kW5.98

How to use the Latent Heat Load Calculator

  1. 1Measure grains of moisture entering and leaving the coil with a psychrometric app.
  2. 2Enter airflow and the grain difference.
  3. 3Compare against the equipment's rated latent capacity.

Frequently asked questions

Typical grain drop?

A well-performing residential coil removes 15-30 grains per pound.

Low latent removal?

Usually too much airflow across the coil or an oversized system that short cycles.

About this calculator