Dehumidifier Sizing Calculator (Pints per Day)

Dehumidifiers are sized by how much water they pull from the air in a day, measured in pints per 24 hours. The long-standing ENERGY STAR and US Department of Energy sizing table sets that capacity from two things: the floor area of the space and how damp it feels.

The table starts at 500 square feet and steps up in even increments. A moderately damp space — musty only in humid weather — needs 10 pints per day at 500 square feet and about 4 more for every additional 500 square feet. A wetter space needs more per step: 5 pints per 500 sq ft when very damp, 6 when wet, and 7 when there is visible seepage. So a 1,000 square-foot basement that is moderately damp lands at 14 pints per day, and the calculator rounds that up to the nearest stocked unit — a 20-pint model.

One catch worth knowing: the DOE changed how dehumidifiers are tested in 2019, measuring capacity at a cooler, drier condition. A unit that would have been labeled 50-pint under the old test is now marked around 30 to 35 pints, even though it removes the same water. Size to the pints-per-day this table gives you and match it to a unit's real performance, not just the nameplate number. For a persistently wet basement, fixing drainage and grading matters as much as the machine.