A 35-pint dehumidifier (new rating) is the right size for most damp basements and rooms around 1,000 sq ft. Small rooms that are only a little damp can use a 20 to 22-pint model, and wet spaces or bigger areas need 50 pints.
Put your space into the calculator below for a specific number. It follows Energy Star’s current sizing table, which is written for the new pint ratings on dehumidifiers sold since 2020.
What Do the Damp Levels Mean?
Pick the level that matches the worst the space gets, not a good day. If you own a humidity meter, the readings below are Energy Star’s ranges for each level.
| Level | What you notice | Humidity |
|---|---|---|
| Moderately damp | Feels damp, musty smell now and then | 50–75% |
| Very damp | Always smells damp, damp spots on walls or floor | 75–90% |
| Wet | Walls or floor sweat, or water seeps in | 90–100% |
| Extremely wet | Wet floors, or laundry drying in the space | — |
Energy Star stops at “wet”. The extremely wet row comes from AHAM’s older sizing chart, which the calculator uses for that level and for spaces over 2,000 sq ft. If the floor is wet, find the leak first; a dehumidifier can’t keep up with running water.
Why Is a 70-Pint Dehumidifier Now Called a 50?
The machines didn’t shrink; the test changed. Since June 2019, the Department of Energy tests portable dehumidifiers at 65°F instead of 80°F. Cooler air holds less water, so the same machine pulls out fewer pints a day and gets a lower number on the box.
Energy Star’s rough conversion looks like this. It notes the real change varies by model, so check the maker’s own numbers when you can.
| Old label (80°F test) | New label (65°F test) |
|---|---|
| 50 pints | About 30 pints |
| 60 pints | About 35 pints |
| 70 pints | About 40–45 pints |
Whole-home units changed less: Energy Star lists an old 200-pint model at about 170 on the new test.
How Do You Read a Dehumidifier Label?
- Look for “2019 DOE” next to the pint number. That’s the new rating, and it’s the one the calculator gives you.
- Some boxes show both numbers, like “50 pint (2019 DOE), previously 70 pint”. Compare models using the 2019 number.
- Used or older units almost always show the old rating. Use the “older label” number from the calculator for those.
- Ignore the square-foot claim. “Covers 4,500 sq ft” is marketing. The DOE test measures pints per day, not coverage, so compare pints.
Should You Size Up?
If you land between two sizes, I recommend the bigger one. A larger unit reaches your target humidity and cycles off, while an undersized one runs all day and may never get there.
A tall ceiling or laundry in the room pushes you up a size, and the calculator accounts for both. A basement doesn’t change the number, because the new 65°F test was chosen to match basement conditions. In a colder space, expect less water than the label says.
What Humidity Should You Set?
The EPA recommends keeping indoor humidity below 60%, ideally between 30% and 50%. Set the dehumidifier’s humidistat in that range and let it cycle on and off. If you plan to run it around the clock, read whether dehumidifiers are safe to leave on first.
Can One Dehumidifier Handle the Whole House?
A portable unit handles one area. When the calculator says you need more than 50 pints, use two portables in different spots or a whole-home unit tied into your ductwork. There’s more on that choice in how many dehumidifiers you need for your house.
Big portables draw real power, so give each one its own outlet where you can. If yours keeps shutting off, here’s why a dehumidifier can trip a breaker.
Frequently Asked Questions
What size dehumidifier do I need for a 1,000 sq ft basement?
Energy Star puts a space under 2,000 sq ft at 25 to 40 pints if it’s very damp. For 1,000 sq ft that works out to about 33 pints, so a 35-pint model. If the walls sweat or water seeps in, go with 50 pints.
Is a new 50-pint dehumidifier the same as an old 70-pint?
Often, yes. Many makers now sell their old 70-pint size as a 50-pint “2019 DOE” model. Energy Star’s rough conversion is more cautious (an old 70 is about 40 to 45 new), so check the maker’s specs if both numbers matter to you.
What size dehumidifier do I need for a bathroom or small bedroom?
A 20 to 22-pint model (new rating) covers a small room that’s damp but not wet. If the bathroom has no exhaust fan, fix that first; a fan removes shower steam at the source.
Does a bigger dehumidifier use more electricity?
It draws more while running, but it also reaches your target sooner and shuts off. An Energy Star certified model is the simplest way to keep the running cost down at any size.
The Bottom Line
Measure the floor, be honest about how damp it gets, and buy on the new “2019 DOE” pint number. When in doubt, go one size up. Next, read whether it’s safe to leave a dehumidifier on all the time.
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