Dehumidifier size calculator: what size dehumidifier do I need?
25 to 40 pints per day
Very damp, 75 to 90% humidity · room under 2,000 sq ft · for 1,000 sq ft
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25 to 40 pints per day
Very damp, 75 to 90% humidity · room under 2,000 sq ft
Source: ENERGY STAR, Dehumidifiers: recommended capacity range in pints per day by condition and room size (U.S. EPA), read November 7, 2026. Read the source
A very damp 1,000 square foot basement, 75 to 90 percent humidity, needs a portable dehumidifier of 25 to 40 pints per day by the ENERGY STAR chart for rooms under 2,000 square feet; over 2,000, at least 40.
A worked example
A 640 sq ft crawl space where a hygrometer reads 92% and the air sits at 58°F needs 30 to 50 pints per day. 92% is in the wet row, 90 to 100%: 30 to 50 pints a day for a space under 2,000 sq ft. At 58°F, under 65°F, ENERGY STAR points to a model rated for low temperatures.
What size dehumidifier for a basement?
Under 2,000 sq ft: 20 to 30 pints a day if it smells musty now and then, 25 to 40 if it always smells damp with damp spots, 30 to 50 if the walls or floor sweat. Over 2,000 sq ft: at least 30, 40 or 50.
What size dehumidifier for 1,500 sq ft?
The same row as 1,000 sq ft, because ENERGY STAR splits rooms only at 2,000 sq ft: very damp, 25 to 40 pints a day; wet, 30 to 50.
What else it is called
Also searched as a dehumidifier size calculator, a dehumidifier size chart, or what size dehumidifier for a basement, for 1000 sq ft or for a crawl space. ENERGY STAR gives two room sizes, not pints per square foot, so 1,000 and 1,500 sq ft take the same row.
The ENERGY STAR capacity chart
| Condition | Room under 2,000 sq ft | Room over 2,000 sq ft |
|---|---|---|
| Slightly to moderately damp, 50 to 75% humidity | 20 to 30 pints per day | 30+ pints per day |
| Very damp, 75 to 90% humidity | 25 to 40 pints per day | 40+ pints per day |
| Wet, 90 to 100% humidity | 30 to 50 pints per day | 50+ pints per day |
ENERGY STAR, Dehumidifiers: recommended capacity range for a portable dehumidifier, the minimum capacity to buy. Better to oversize than undersize. Below 65°F, a model specified for low temperatures.
Where the numbers come from
- ENERGY STAR, Dehumidifiers, recommended capacity range in pints per day, small to medium room (under 2,000 sq ft) and large room (over 2,000 sq ft): slightly to moderately damp, 50 to 75% relative humidity, 20 to 30 and 30+; very damp, 75 to 90%, 25 to 40 and 40+; wet, 90 to 100%, 30 to 50 and 50+. Read November 7, 2026. ENERGY STAR guide
- ENERGY STAR: “Use the charts below to estimate the minimum capacity for your portable dehumidifier.” “It’s better to oversize than undersize!” Where temperatures typically fall below 65°F, consider a product specified for use at lower temperatures. ENERGY STAR guide
- A humidity of exactly 75 or 90 percent is on two rows, and exactly 2,000 sq ft on both room sizes: this page takes the wetter row and the large room, as the guide says to oversize rather than undersize. A humidity you measured picks the row over the description.
The chart is for portable dehumidifiers; ENERGY STAR sizes whole home units in a separate guide. It also notes that capacity options have changed with a new DOE rating method: the pints here are the current ratings.
By Javier Miralles · Last updated . How this site is made.
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