Choosing the Right Dehumidifier
High humidity can make your home uncomfortable and lead to problems like mold and mildew. A dehumidifier is the solution, but choosing the right size is critical for it to be effective.
Last updated: November 8, 2025
The New DOE Sizing Standard (2019)
Dehumidifier testing standards changed in 2019. New models are tested at a lower, more realistic temperature (65°F vs. 80°F), so their pint capacity ratings appear lower. The key takeaway is:
A new 35-pint model is roughly equivalent to an old 50-pint model.
Our calculator uses the older, more commonly understood sizing convention, but be aware of this change when shopping.
Sizing Your Dehumidifier
Sizing depends on two main factors: the square footage of the space and its initial moisture level.
1. Determine the Moisture Level:
- Moderately Damp: The air feels clammy or sticky, and you may notice a slight musty odor.
- Very Damp: The air smells musty, and you see dark stains on walls or floors.
- Wet: You can see moisture beads (condensation) on walls or floors, or you experience some seepage.
- Extremely Wet: The area has standing water or obvious, active leaks. (You should fix leaks before running a dehumidifier).
2. Measure the Area:
Calculate the square footage (length x width) of the room you need to treat. For oddly shaped rooms, break them into smaller rectangles and add the areas together.
Essential Dehumidifier Features
Continuous Draining
Constantly emptying a collection bucket is a chore. Look for models with a connection for a standard garden hose to allow for continuous, gravity-fed draining into a floor drain or sump pump.
Built-in Pump
If you need to drain water upwards (e.g., into a utility sink), a model with a built-in condensate pump is a must-have feature. It provides much more flexibility for placement.
Humidistat
An adjustable humidistat allows you to set your desired humidity level (typically 45-50%). The unit will automatically cycle on and off to maintain that level, saving energy and preventing the air from becoming too dry.
Auto-Defrost
Essential for use in cool spaces like basements. This feature prevents the unit's coils from icing over when operating at lower temperatures, which would stop it from working.