Dehumidifier Sizing Calculator

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.