Buying guide
What Size Dehumidifier Do I Need? The Sizing Chart
Reviewed by
Dr. Yocheved Yorkovsky · Science Editor, Health, Chemistry & Environment
Size by square footage and how damp the space actually is — and remember post-2019 pint ratings run about a third lower than the old ones.
Match a dehumidifier to my room →Chart and pricing checked July 2026.
The quick answer
Capacity depends on two things, not one: the room's square footage, and how damp it actually is. The damper the space, the more capacity you need for the same floor area.
The sizing chart
Capacity in pints per day, under the current 2019 DOE standard, for an 8-foot ceiling:
| Room size | Moderately damp (musty in humid weather) | Very damp (musty most of the time) | Wet (damp walls, visible spots) |
|---|---|---|---|
| 500 sq ft | 20 pint | 20–25 pint | 25–30 pint |
| 1,000 sq ft | 25–30 pint | 30–35 pint | 40–45 pint |
| 1,500 sq ft | 30–35 pint | 40–45 pint | 50 pint |
| 2,000 sq ft | 40–45 pint | 50 pint | 50+ pint |
| 2,500 sq ft | 50 pint | 50+ pint | 50+ pint, or two units |
| 3,000+ sq ft | 50+ pint | Two units | Two units |
A 1,000 sq ft basement that's moderately damp needs about a 25–30-pint. The same room with visible seepage wants closer to a 50-pint. Same floor area, nearly double the machine.
Adjust for the room
Add capacity for any of these:
- Tall ceilings. Adjusted size = square footage × ceiling height ÷ 8. A 1,000 sq ft room with 10-foot ceilings behaves like a 1,250 sq ft room.
- Below grade. A basement runs cooler and damper than its square footage suggests — add roughly 5 pints.
- No vapor barrier, or a dirt-floor crawl space — add 5–10 pints.
- High occupancy or a laundry in the space — add about 5 pints.
Why the pint number changed
In 2019 the DOE moved its capacity test to a cooler 65°F condition. Cooler air holds less moisture, so the same machine now posts a lower figure — an old 70-pint is today's 50-pint. If you're replacing an old unit, don't match the old number or you'll significantly oversize. Full explanation here.
And watch for the other trick: a "MAX pint" figure is measured at 95°F/90% RH, a condition no home ever sees. A unit sold as "80 MAX pints" can be a 32-pint under the real standard.
Is it better to oversize or undersize?
Oversize, within reason. An undersized dehumidifier runs continuously and never quite reaches your target humidity — which costs more in electricity and wear than a slightly larger unit that hits target and cycles off.
The economics agree. Our pints-per-dollar study found the largest units deliver 83% more water per dollar than the smallest. Capacity is the cheapest thing you can buy here.
Our picks by size
| Space | Pick | Capacity |
|---|---|---|
| Bedroom, office, small apartment | Midea Cube 20 | 20 pints/day |
| Normal damp room | Midea Cube 35 | 35 pints/day |
| One damp room, tight budget | Waykar 34 | 34 pints (95°F rating) |
| Damp basement, whole floor | Frigidaire FHDD5034 | 49.7 pints/day |
| Basement with no floor drain | Midea Cube 50 (pump) | 50 pints/day |
| Cold garage or crawl space | Ivation IVADDH06 | 12 pints (desiccant) |
What the chart doesn't tell you
Sizing gets you the right capacity. It doesn't tell you how often you'll empty the thing — and that varies nearly eightfold across these units, which we measured in days between empties. If you can't run a drain hose downhill, tank size matters more than pints.
Sources
- ENERGY STAR: dehumidifier testing and capacity
- ENERGY STAR: dehumidifiers
- EPA: mold and moisture — the 30–50% RH target
Bottom line
Find your square footage, be honest about how damp the space really is, add capacity for ceiling height and below-grade, and round up. If you'd rather not do the arithmetic, the quiz asks about the space in plain language and sizes it for you.
Frequently asked
Is it better to oversize or undersize a dehumidifier?
Oversize, within reason. An undersized unit runs constantly and never reaches your target humidity; a slightly larger one hits target faster and cycles off, often using less energy overall. Larger units are also better value per pint.
How do old pint ratings compare to new ones?
Roughly 30% lower under the 2019 standard. An old 70-pint is about a new 50-pint, and an old 50-pint is about a new 30–35-pint. Same performance, different label — so don't match your old unit's number.
Does ceiling height matter?
Yes. Multiply square footage by ceiling height and divide by 8. A 1,000 sq ft room with 10-foot ceilings behaves like a 1,250 sq ft room, and needs capacity to match.
What size dehumidifier for a 1,000 sq ft basement?
About a 25–30-pint if it's only moderately damp. If it's very damp, step up to 30–35 pints; if there's visible seepage or damp walls, you want closer to a 50-pint. Below-grade spaces also warrant about 5 extra pints.
What does 'MAX pint' mean?
It's capacity measured at 95°F and 90% relative humidity — conditions no home experiences. It inflates the number substantially. Always look for the 2019 DOE rating instead.