Which dehumidifier size do you need for a basement?
Updated
Choose capacity by how damp the space feels and how large it is, not by square footage alone. Use the ENERGY STAR pint chart, then check humidity with a meter.
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Step 1: Measure the humidity before you shop
Capacity depends on how wet the air is, so a reading matters more than guessing. The EPA says to keep indoor humidity below 60%, ideally between 30% and 50%, and that a humidity meter costs about $10 to $50. Put a meter in the room for a couple of days, in the same spot, away from the walls, and note the high and low. If you read above 60% for days, you need a dehumidifier. If readings swing with the weather, you may only need one in summer.
Also look for the source. Condensation on windows or cold pipes, a musty smell and damp walls point to different problems. ENERGY STAR suggests reducing moisture where you can: extend downspouts, keep gutters clear, slope soil away from the foundation, vent the dryer outdoors, use bathroom and kitchen fans and fix leaking outdoor faucets. A dehumidifier works better when it is not fighting a leak.
Step 2: Match pints per day to dampness
| How the space feels without a dehumidifier | Under 2,000 sq ft | Over 2,000 sq ft |
|---|---|---|
| Slightly to moderately damp (50–75% RH) | 20–30 pints a day | 30+ pints |
| Very damp (75–90% RH) | 25–40 pints | 40+ pints |
| Wet (90–100% RH) | 30–50 pints | 50+ pints |
These ranges are from ENERGY STAR. The agency adds that it is better to oversize than undersize. If you are replacing a unit, you can also estimate the capacity you need from how much water you empty each day. Compare pint ratings only between listings that name the same test standard, since the labeling method has changed over the years.
Step 3: Choose the drain
A basement unit that fills a bucket in a day or two will keep shutting itself off. A hose fitting that drains to a floor drain or sump pump, or a pump that lifts the water to a sink, lets the unit work while you are away. Our comparison of bucket and continuous drain setups goes through the costs and risks.
Step 4: Check the temperature range
Basements are cool. ENERGY STAR notes that frost can form on a dehumidifier’s coils when the air falls below 65°F, which can cause short cycling. Units with an anti-frost sensor switch off at a set low temperature; others need you to turn them off and let them defrost. If your basement stays cold in winter, look for a low-temperature rating on the spec sheet.
What it costs to run
The Department of Energy’s formula is watts × hours ÷ 1,000 for kilowatt-hours, then kWh × your rate. A 450 W unit running 12 hours a day uses 5.4 kWh, which at 18¢ per kWh is about $0.97 a day or $29 a month. The EIA forecasts a 2026 average residential price of about 18.2¢, but rates vary by state. ENERGY STAR certified dehumidifiers use 20% less energy than a similarly sized conventional unit to remove the same moisture. Try your own numbers in our device energy cost calculator.
Whole-house units and special cases
- Whole-home dehumidifiers make sense in a humid climate with central air conditioning when humidity stays above 55% throughout the house. They usually have a drain only, and ENERGY STAR advises that an HVAC professional route it to a floor drain or pump.
- Crawlspaces and unfinished basements with exposed soil need moisture sources dealt with first. A dehumidifier alone will not keep up with an open dirt floor.
- A basement that floods or seeps needs drainage work and a sump pump, not just a dehumidifier. See our sump pump alarm guide.
- Keep hoses away from electrical cords and circuits, as ENERGY STAR warns, and place a leak sensor under the unit.
Shop by need
Damp basement up to about 2,000 sq ft
What to look for: 25–40 pint capacity, humidistat, continuous drain or built-in pump, ENERGY STAR, anti-frost sensor
Typical price: $200–$450
See options on AmazonWet basement or larger space
What to look for: 50+ pint capacity, built-in pump with listed lift height, low temperature operation, washable filter
Typical price: $300–$650
See options on AmazonChecking humidity first
What to look for: digital hygrometer with min and max memory, placed at room level, battery powered
Typical price: $10–$30
See options on AmazonFrequently asked questions
What size dehumidifier do I need for a 1,000 sq ft basement?
If it feels damp, ENERGY STAR points to 20–30 pints a day; if it is very damp or wet, 25–50 pints. Oversizing is better than undersizing, and a hygrometer shows if it keeps up.
What humidity should a basement be?
The EPA says to keep indoor humidity below 60%, ideally 30%–50%. In cold climates in winter, ENERGY STAR suggests 30%–40% to limit window condensation.
Do dehumidifiers work in a cold basement?
They struggle below 65°F because frost can form on the coils. Choose a model with an anti-frost sensor or a low-temperature rating, and defrost it when needed.
Is a bigger dehumidifier always better?
Within reason. ENERGY STAR advises oversizing rather than undersizing, but a unit that is far too large for a tiny space can cost more upfront without helping.