Dehumidifier sizing Last reviewed June 2026
What Size Dehumidifier for a Crawl Space?
By the WhatSize editorial team 5 min read Standards-reviewed
For most crawl spaces, a 35-pint dehumidifier is sufficient if the space is encapsulated. For vented or very damp crawl spaces, choose 50-70 pints.
Why Crawl Spaces Are Different from Basements
Crawl spaces are more challenging to dehumidify than basements because they're usually smaller, harder to access, and often have direct contact with soil. An unencapsulated crawl space has exposed dirt floors, which constantly release moisture into the air.
The first step in any crawl space dehumidification project should be encapsulation — sealing the floor with a vapor barrier and closing foundation vents.
Top picks for this size
These Amazon-available picks meet the calculated spec. For region-specific or licensed contractor-installed options, consult a local professional. See our Disclaimers.
Encapsulated vs. Vented: How It Affects Sizing
- Encapsulated crawl space (sealed, vapor barrier): 35-50 pints for up to 1,500 sq ft
- Vented crawl space (open to outside air): 70+ pints, but encapsulation is strongly recommended first
Frequently asked questions
What size dehumidifier do I need for a crawl space?
Technically yes, but it's not ideal. Crawl space conditions call for a unit designed for the environment with durable construction and automatic restart after power outages.
How do I drain a dehumidifier in a crawl space?
A condensate pump is essential for crawl space dehumidifiers. The pump pushes water up and out through a small-diameter tube to a drain or outside.
What happens if my crawl space is too humid?
Excess crawl space humidity causes mold growth on floor joists, wood rot, increased risk of termites, and musty odors that migrate into living spaces above.
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More dehumidifier sizing guides
- What Size Dehumidifier for a 500 Sq Ft Room?
- What Size Dehumidifier for a 1,000 Sq Ft Space?
- What Size Dehumidifier for a 1,500 Sq Ft Space?
- What Size Dehumidifier for a 2,000 Sq Ft Space?
- What Size Dehumidifier for a Basement?
- What Size Dehumidifier for a Bedroom?
- 50-Pint vs 70-Pint Dehumidifier: Which Size Do You Need?
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