Best Dehumidifier for a Basement
Short answer: basements run cool and damp, so we size them as at least very damp. A typical 1,000 sq ft damp basement needs about 17 pints/day — a 20-pint unit with continuous drainage; a wet 1,000–1,500 sq ft basement steps up to a 30-pint unit, and a large or very wet basement to a 50-pint unit. Always run continuous drainage so you're not emptying a tank by hand.
A basement is the classic dehumidifier job: cool air, damp walls in contact with the soil, and a musty smell that won't quit. Because below-grade air holds less moisture before it condenses, a basement feels damp even when the same room upstairs would feel fine — so we always size a notch up and run continuous drainage. Here's the right capacity and honest picks by class. Product links are Amazon affiliate links and never change the advice.
Basement sizing at a glance
| Basement | Calculation (post-2020 scale) | Recommended unit |
|---|---|---|
| ~1,000 sq ft, damp | base 14 × 1.2 (very damp min) = 17 pints/day | 20-pint + continuous drainage |
| ~1,500 sq ft, wet | base 18 × 1.4 = 26 pints/day | 30-pint + continuous drainage |
| ~2,000 sq ft, very wet | base 22 × 1.6 = 36 pints/day | 50-pint + continuous drainage |
Basements are treated as at least very damp (×1.2), even if you'd call yours just "damp." Run your exact basement →
Basement dehumidifiers by capacity class
Pick the class that matches your sizing result above. Confirm the current pint rating (2020 scale) and that the unit offers continuous drainage before buying.
20-pint — smaller or merely damp basements:
30-pint — the typical wet basement:
50-pint — large or very wet basements:
We earn commission on qualifying Amazon purchases at no cost to you. See our affiliate disclosure. Pint ratings and prices change — verify the current capacity before buying.
Why basements always size up
Below-grade air is cooler, and cool air holds less moisture before it condenses on walls and floors. That's why a basement reads damp even when the upstairs of the same square footage feels dry. Run continuous drainage — a gravity hose to a floor drain, or a unit with a built-in pump if the drain sits higher than the dehumidifier — so the unit keeps working unattended and you're not carrying a full tank up the stairs. Keep doors and windows shut while it runs, and give the intake and exhaust clear airflow.
Frequently asked questions
What size dehumidifier do I need for a basement?
Treat it as at least very damp. ~1,000 sq ft damp basement ≈ 17 pints/day (20-pint); wet 1,000–1,500 sq ft ≈ 26 (30-pint); large/very wet ≈ 36 (50-pint). Run continuous drainage.
Should a basement dehumidifier drain continuously?
Yes — use a gravity hose to a floor drain, or a built-in pump if the drain is higher than the unit, so you're not emptying a tank daily.
Where should a dehumidifier sit in a basement?
Centrally, with clear airflow around the intake/exhaust, away from walls and clutter, near a drain for continuous drainage. Keep doors and windows closed while it runs.
Related: Dehumidifier Sizing Calculator · What Size Dehumidifier Do I Need? · Best for 1,500 sq ft · Best for a Crawl Space