What size dehumidifier do I need?

Where the numbers come from

The size comes from ENERGY STAR's dehumidifier chart. It asks two things: how big the space is (under or over 2,000 sq ft) and how damp it is without a dehumidifier. ENERGY STAR calls the answer the minimum capacity, and adds:

“Remember, it’s better to oversize than undersize!”ENERGY STAR, Dehumidifiers

Old pints and new pints

In 2019 the Department of Energy changed the test. Portable units are now tested at 65°F instead of 80°F, closer to a basement. Cooler air gives up less water, so the same machine now reports fewer pints.

“This 15°F reduction in testing temperature means that a dehumidifier tested to the new procedure will likely report a smaller capacity than when tested to the old procedure.”ENERGY STAR, Dehumidifier Testing and Capacity

ENERGY STAR's own table puts an old 70-pint unit at about 40 to 45 pints today, and an old 50 at about 30. It calls that a rough guide that varies by model. The tool uses only the rows ENERGY STAR prints and never guesses between them.

Which pints is the chart in? ENERGY STAR put this chart up in early 2020, beside that table, replacing an older chart from the appliance makers' association (AHAM) that was written in the old pints. So the tool reads the chart as today's pints and compares it straight to each model's capacity on ENERGY STAR's list, which is measured on today's test. Nothing is converted.

Some boxes still lead with the old 80°F number, mostly whole-house and crawl space units. AprilAire's E080 is sold as 80 pints; its own spec sheet lists 65 at the DOE's 73°F whole-home test. The cards below show both numbers when they differ.

Humidity to aim for

“If possible, keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity.”EPA, A Brief Guide to Mold, Moisture and Your Home

Safety

“Never set up water drainage or disposal near electrical circuits or devices. Make sure the dehumidifier is connected to a properly grounded outlet. Keep drain hoses away from electrical cords and connections.”ENERGY STAR, Dehumidifiers: placement

Sources, retrieved October 30, 2026: ENERGY STAR, Dehumidifiers (sizing chart, placement, humidity) · ENERGY STAR, Dehumidifier Testing and Capacity (old vs new pints) · ENERGY STAR certified dehumidifiers list · DOE test procedure, 10 CFR 430 Appendix X1 · EPA, A Brief Guide to Mold, Moisture and Your Home.

Questions

What size dehumidifier do I need for a basement?

Under 2,000 sq ft, ENERGY STAR's chart says 20 to 30 pints a day if the space is slightly to moderately damp, 25 to 40 if it's very damp, and 30 to 50 if it's wet. Over 2,000 sq ft it gives a minimum of 30, 40 or 50 pints. If the basement often sits below 65°F, ENERGY STAR suggests a model specified for lower temperatures.

Is a 50-pint dehumidifier the same as an old 70-pint one?

Not by ENERGY STAR's table. It puts an old 70-pint portable at about 40 to 45 pints on today's test, an old 50 at about 30, and an old 90 at about 55. ENERGY STAR calls this a rough correlation: the change varies by model, and the maker may have a better comparison.

Is it better to buy a bigger dehumidifier?

ENERGY STAR says yes: it's better to oversize than undersize. Its chart gives the minimum capacity for the space.

What humidity should I set it to?

EPA says keep indoor humidity below 60 percent, ideally between 30 and 50 percent. ENERGY STAR adds that in colder climates, during the heating season, 30 to 40 percent helps prevent window condensation.

Why does a whole-house dehumidifier list two pint ratings?

Makers often list pints at 80°F and 60% humidity, the older rating point. The DOE rating for whole-home units is at 73°F and 60% humidity. AprilAire's E080 spec sheet shows both: 80 pints at 80°F and 65 at 73°F. ENERGY STAR lists the DOE figure.

Can a dehumidifier dry out a flooded basement?

Stop the water first. EPA says that if wet or damp materials are dried within 24 to 48 hours after a leak or spill, in most cases mold will not grow. After a lot of water damage, or mold over 10 square feet, EPA points to its mold remediation guide and a contractor with mold cleanup experience.