Dehumidifier Size Calculator: How Many Pints Do You Need?
Dehumidifier size is the pints of water it removes per day, and the right size depends on the area and how damp it is. ENERGY STAR recommends 20–30 pints for a damp space under 2,000 sq ft, 25–40 for a very damp one and 30–50 for a wet one. Enter the space's size and condition to get a capacity, the common unit size to buy, and whether you have outgrown a portable unit.
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- Capacity needed
- 32 pints/day
- 2019 DOE rating, the one on new units' boxes.
- Size to buy
- 35-pint portable
- Round up: a slightly larger unit runs less and lasts longer.
- Area
- 1,200 sq ft
- ENERGY STAR range for this condition
- 25–40 pints (< 2,000 sq ft)
- Rough equivalent on pre-2019 ratings
- about 46 pints
- Older units were tested at 80 °F, so their pint ratings read about 40% higher for the same machine.
Estimates use typical US material and labor pricing. Confirm quantities against the coverage chart on the bag before you buy.
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Prices as of Oct 11, 2026, 4:41 AM UTC. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
How this calculator works
- Up to 2,000 sq ft: pints = low + (high − low) × (area − 500) ÷ 1,500, using ENERGY STAR's range for the condition (500 sq ft gets the low end, 2,000 sq ft the high end).
- Over 2,000 sq ft: ENERGY STAR's floor (30, 40 or 50 pints) plus 4, 5 or 6 pints for each extra 500 sq ft, the steps of the older AHAM chart.
- Pre-2019 equivalent ≈ pints ÷ 0.7 (DOE moved the test from 80 °F to 65 °F in June 2019).
Dehumidifier size by area and condition (pints per day, 2019 DOE rating)
| Area | Damp | Very damp | Wet |
|---|---|---|---|
| 500 sq ft | 20 pints | 25 pints | 30 pints |
| 1,000 sq ft | 23 pints | 30 pints | 37 pints |
| 1,500 sq ft | 27 pints | 35 pints | 43 pints |
| 2,000 sq ft | 30 pints | 40 pints | 50 pints |
| 2,500 sq ft | 34 pints | 45 pints | 56 pints |
| 3,000 sq ft | 38 pints | 50 pints | 62 pints |
Source: ENERGY STAR, Dehumidifiers — recommended capacity ranges (checked October 11, 2026); values between are interpolated by area.
Why dehumidifier sizes changed in 2019
Until June 2019, capacity was measured at 80 °F and 60% relative humidity. The Department of Energy's current test uses 65 °F, closer to a real basement, and colder air holds less water, so the same machine now carries a smaller number. A unit sold as 70 pints before 2019 is typically labeled about 50 pints today. When you compare an old unit with a new one, compare like with like; ENERGY STAR notes that capacity labels changed for this reason.
Basements and crawl spaces
Most basements are 'very damp' by ENERGY STAR's description: a musty smell all the time and damp spots on walls or floors. Fix the water sources first — gutters, downspouts that drain at the foundation, grading that slopes toward the house — then size the dehumidifier for what's left. In a crawl space that is being encapsulated, the dehumidifier is sized for the sealed volume and usually drains to a sump or condensate pump.
Aim for 30% to 50% relative humidity indoors; a cheap hygrometer tells you whether the unit is keeping up. If it runs nonstop and the humidity stays above 60%, it is too small or the space has a water problem.
Portable or whole-home?
Portable units top out around 50 pints a day (2019 rating). Past that, a ducted whole-home dehumidifier is quieter, drains itself and treats several rooms. Two portable units on opposite ends of a large basement also work and keep you covered if one fails.
Keep going
- Sealing the crawl space too? crawl space encapsulation cost calculator
- Will a cold wall sweat at this humidity? dew point calculator
- Insulating the basement walls: basement insulation calculator
Frequently asked questions
What size dehumidifier do I need for a basement?
A 1,000 sq ft basement that is very damp needs about 30 pints a day, so a 30- or 35-pint unit; a 1,500 sq ft basement about 35 pints, a 35-pint unit. Wet basements with seepage need 35 to 50 pints.
What size dehumidifier for 2,000 square feet?
ENERGY STAR's chart tops its small-medium column at 2,000 sq ft: 30 pints if damp, 40 if very damp and 50 if wet. Above 2,000 sq ft it recommends 30+, 40+ and 50+.
Is a bigger dehumidifier better?
Within reason, yes. ENERGY STAR says it is better to oversize than undersize: a larger unit reaches the target humidity and cycles off, while an undersized one runs constantly and may never get there.
What humidity should I set my dehumidifier to?
Between 30% and 50% relative humidity. Below about 30% the air gets uncomfortably dry; above 60% mold and dust mites thrive.
Why does my old 70-pint dehumidifier say 50 pints now?
It doesn't — new units are rated under DOE's 2019 test at 65 °F instead of 80 °F. The same capacity class that used to be labeled 70 pints is labeled about 50 pints today.
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Capacity needed
32 pints/day