Dehumidifier Size Calculator
Instructions:
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Review the methodology to ensure it aligns with your project's requirements.
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Enter Units: Pints/day, BTU/h, or kW
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Use Slider to select the required capacity.
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A list of dehumidifier options will populate the table.
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In the results table, clicking on one of the "Manufacturer & Model" buttons will bring you to the manufacturer's specification sheet.
Dehumidifiers are catalogued in pints per day, but a latent load usually arrives in BTU/h or kW. Enter the load in whichever unit you have and the first three results restate it in all three, using water's latent heat of condensation: pints/day = BTU/h / 1.04 lb/pint x 24 h/day / 1055 BTU/lb, and 1 kW = 3412.142 BTU/h.
Only the box matching the selected unit is read, so a figure left in one of the other two from an earlier run cannot affect the answer.
The list of units above is the manufacturers' catalogue this calculator ships with, each unit's rated pints/day restated in BTU/h and kW. Take the first unit whose capacity meets or exceeds the required capacity; units of equal rating are alternates. Capacities and prices come from the manufacturers' published figures as of an internet search on 1/2/2024, and the prices are approximate.
876 pints/day is the largest single unit in the catalogue, about 40,047 BTU/h or 11.73 kW. Above that the warning appears and the load needs more than one machine.
Corrected 2026-09: the previous version of this calculator threw away a capacity typed in scientific notation. Entering 1e3 pints/day answered zero and gave no sign that it had ignored the entry. It now reads as the 1000 pints/day you meant.
Use this as a preliminary selection only. Confirm the final choice against the manufacturer's literature and a licensed engineer.
Results are at 80°F / 60% RH Entering Air
Methodology & Equations:
Although dehumidifiers are rated in units of Pints/day, engineers must often select dehumidifiers given the latent load in either BTU/h or kW. Using Adicot's calculator, you can enter the dehumidifier capacity in Pints/day, BTU/h, or kW. Regardless of your input, this calculator will select a dehumidifier based on the methodology and equations below. This calculator was developed out of necessity due to the limited number of tools engineers have to size dehumidifiers. This calculator is recommended to be used as a preliminary equipment selection tool, and the final equipment selection should be verified with the manufacturer and engineer.
The calculator selects dehumidifier(s) based on the manufacturer's rated Pints/day capacity. Users can enter the capacity in Pints/day, Btu/h, or kW.
If the user enters the capacity in Btu/h, the calculator first converts that capacity to Pints/day using the equation:
Pints/day = BTU/h / 1.04 lb/pint x 24 hrs/day / 1055 BTU/lb
Example: The space has an excess latent load of 4,100 BTU/h. Convert this value to Pints/day
Pints/day = 4,100 BTU/h / 1.04lb/pint x 24 h/day / 1055 BTU/lb = 90 Pints/day
Similarly, if the user enters the capacity in kW, the calculator first converts that capacity to pints per day using the equation:
Pints/day = kW x 3412.142 BTU/h / kW / 1.04 lb/pint x 24 hrs/day / 1055 BTU/lb
Example: The space has an excess latent load of 1.2 kW. Convert this value to Pints/day
Pints/day = 1.2 kW x 3412.142 BTU/h / kW / 1.04lb/pint x 24 h/day / 1055 BTU/lb = 90 Pints/day
The pints per day are then compared to the manufacturer's literature to provide a list of matching dehumidifier(s). The dehumidifiers shown will meet and/or exceed your entered capacity.