Choosing the right size dehumidifier depends on how much moisture is in the air, not just the size of the room.
A unit that is too small will run constantly and still struggle. A unit that is slightly oversized usually performs better and lasts longer.
Dehumidifier sizing is about moisture load, not just square footage.
If you have not confirmed that excess moisture is actually the problem in your home, start with our overview of common wet-house humidity problems.
What Does the Number on a Dehumidifier Mean?
The number on a dehumidifier refers to how many pints of moisture it can remove from the air in 24 hours under standard test conditions.
For example, a 30-pint unit can remove up to 30 pints per day. A 50-pint unit can remove up to 50 pints.
This number does not describe room size. It describes moisture removal capacity.
A higher pint rating means the unit can handle more moisture over time. Two homes with the same square footage can require very different pint ratings depending on humidity levels, airflow, ceiling height, and how the space is used.
This is why choosing a dehumidifier based on square footage alone often leads to a machine that runs constantly and never quite catches up.
Most residential units fall into these general ranges:
- 30-pint units for smaller spaces or mild humidity
- 40–50-pint units for average homes
- 50–70-pint units for large areas or persistently damp basements
A properly sized dehumidifier should cycle on and off and maintain steady humidity without running all day.
Dehumidifier Size by Square Footage (General Guide)
Square footage is the most common way dehumidifiers are sized, but it should be treated as a starting point, not a final answer.
As a rough guideline:
- Up to 1,000 sq ft: 20–30 pints
- 1,000–2,000 sq ft: 30–50 pints
- 2,000–3,000 sq ft: 50–70 pints
- Basements or very damp spaces: size up one category
Square footage does not account for ceiling height, airflow, insulation quality, or how much moisture is actually entering the space. A tall basement or open floor plan can behave like a much larger area than the numbers suggest.
For a quick reference chart, see:
Dehumidifier Size Chart by Square Footage
Common Home Sizes
If you prefer to size by total home area, start here:
- 1,000 square feet
- 1,500 square feet
- 2,000 square feet
- 2,500 square feet
- 3,000 square feet
- Apartments
Each page breaks down typical pint ranges and explains when you should move up a size.
Basement, Crawlspace, and Garage Sizing
Lower-level and enclosed spaces behave differently than main living areas.
If you are sizing for a specific location, start with:
Crawlspaces in cold climates have additional considerations.
Start With the Size of the Space
Begin with the square footage of the area where humidity is noticeable.
As a general starting point:
- Small rooms and enclosed areas often work with 30–40-pint units
- Medium-sized spaces usually need 40–50-pint units
- Large or open areas often require 50–70-pint units
Ceiling height matters. Taller spaces hold more air and behave like larger rooms.
Adjust for How Damp It Feels
Square footage alone is not enough.
Consider how the space behaves day to day:
- Does it feel slightly damp or consistently wet?
- Are musty smells present?
- Is condensation visible on windows or walls?
General guidance:
- Mild humidity: choose the lower end of the size range
- Noticeable dampness: move up one size
- Persistent moisture: choose the larger option
Undersizing is the most common mistake homeowners make.
Open vs Divided Spaces
Open layouts allow air to circulate more easily and are generally easier to control.
Divided spaces, storage rooms, or areas with closed doors restrict airflow and may require:
- A larger unit
- Multiple units
- More careful placement
Do not assume one small unit can manage multiple separate rooms.
Drainage Matters More Than Most People Expect
How water is removed affects how usable a dehumidifier is over time.
Consider:
- Gravity drain if a floor drain is available
- Built-in pump if water must move upward or across a distance
Units that rely only on buckets often get ignored once they fill too quickly, even if the sizing itself is correct.
Practical Recommendation
If you are between two sizes, choose the larger one.
A dehumidifier that cycles on and off is generally healthier for the machine than one that runs nonstop.
In larger homes or open floor plans, a single portable unit may struggle to control humidity evenly. In those cases, some homeowners consider whole-house dehumidifiers that connect to existing ductwork. These systems are designed for broader coverage but involve higher cost and installation.
Portable Dehumidifier Size Options
Small Dehumidifiers (30–40 pint)
Medium Dehumidifiers (40–50 pint)
Large Dehumidifiers (50–70 pint)