Latent Heat Load Calculator
Moisture removal load from airflow and grain difference.
Enter your values
Enter the airflow in CFM.
Enter the grain difference in gr/lb.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- 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.
BTU/h = 0.68 x CFM x Δgrains
At a glance
| What it does | Moisture removal load from airflow and grain difference. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Airflow, Grain difference |
| Main output | Latent load |
| Formula | BTU/h = 0.68 x CFM x Δgrains |
| Cost | Free — no sign-up, no download |
How to use the Latent Heat Load Calculator
- 1Measure grains of moisture entering and leaving the coil with a psychrometric app.
- 2Enter airflow and the grain difference.
- 3Compare against the equipment's rated latent capacity.
Inputs explained
- Airflow(CFM)
- Enter the airflow in CFM.
- Grain difference(gr/lb)
- Enter the grain difference in gr/lb.
Worked example
Using the values the calculator loads with:
Inputs
- Airflow1200 CFM
- Grain difference25 gr/lb
Results
- Latent load20,400 BTU/h
- In tons1.7
- Water removed19.4 pints/hour
- In kW5.98
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.
What do I need to enter into the Latent Heat Load Calculator?
Just 2 values: airflow, grain difference. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Latent Heat Load Calculator work out the answer?
Latent load equals 0.68 times CFM times the grains of moisture removed per pound of air. It applies the formula BTU/h = 0.68 x CFM x Δgrains and shows the working so you can check each step by hand.
Is the Latent Heat Load Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.