Your result
Enter your numbers and press the button.
How the size is worked out
The calculator scales your area by ceiling height ÷ 8, because both charts assume an 8-ft ceiling and GE says to add 25% at 10 ft. It reads the AHAM pint figure for your dampness level, interpolating between the chart's 500 sq ft steps, and finds the smallest GE model class that covers the area.
| Area | Moderately damp | Very damp | Wet | Extremely wet |
|---|---|---|---|---|
| 400 sq ft | 10 pt | 12 pt | 14 pt | 16 pt |
| 500 sq ft | 10 pt | 12 pt | 14 pt | 16 pt |
| 600 sq ft | 11 pt | 13 pt | 15 pt | 17 pt |
| 700 sq ft | 12 pt | 14 pt | 16 pt | 19 pt |
| 800 sq ft | 12 pt | 15 pt | 18 pt | 20 pt |
| 900 sq ft | 13 pt | 16 pt | 19 pt | 22 pt |
| 1,000 sq ft | 14 pt | 17 pt | 20 pt | 23 pt |
| 1,200 sq ft | 16 pt | 19 pt | 22 pt | 26 pt |
| 1,500 sq ft | 18 pt | 22 pt | 26 pt | 30 pt |
| 1,600 sq ft | 19 pt | 23 pt | 27 pt | 31 pt |
| 1,800 sq ft | 20 pt | 25 pt | 30 pt | 34 pt |
| 2,000 sq ft | 22 pt | 27 pt | 32 pt | 37 pt |
| 2,500 sq ft | 26 pt | 32 pt | 38 pt | 44 pt |
| Condition | 500 sq ft | 1,000 sq ft | 1,500 sq ft | 2,000 sq ft | 2,500 sq ft |
|---|---|---|---|---|---|
| Moderately damp | 10 pt | 14 pt | 18 pt | 22 pt | 26 pt |
| Very damp | 12 pt | 17 pt | 22 pt | 27 pt | 32 pt |
| Wet | 14 pt | 20 pt | 26 pt | 32 pt | 38 pt |
| Extremely wet | 16 pt | 23 pt | 30 pt | 37 pt | 44 pt |
AHAM sizing chart, pints per day, as published by Direct Energy.
| Condition | 22 pint | 35 pint | 50 pint |
|---|---|---|---|
| Mildly damp | 1,500 sq ft | 3,000 sq ft | 4,500 sq ft |
| Slightly damp | 1,000 sq ft | 2,000 sq ft | 3,000 sq ft |
| Very damp | 800 sq ft | 1,400 sq ft | 2,000 sq ft |
| Wet | 500 sq ft | 1,000 sq ft | 1,500 sq ft |
GE Appliances sizing chart. Assumes an 8-ft ceiling; add 25% to the area for 10-ft ceilings.
Which dampness level are you?
- Moderately damp: AHAM describes a space that feels damp and smells musty only in humid weather.
- Very damp: it always feels damp and smells musty, and there may be damp spots on walls or floor.
- Wet: walls sweat or water seeps in.
- Extremely wet: wet floors, standing water, or a high-load space such as a laundry area.
Measure with a hygrometer for a few days before you buy. The EPA advises keeping indoor humidity below 60%, ideally 30%–50%, to keep mold from growing.
Where basement moisture comes from
| Source | Sign | Usual fix |
|---|---|---|
| Rain and snowmelt | Wet floor edges after storms | Gutters, downspout extensions, grading |
| Groundwater | Water through cracks or under walls | Interior drain and sump pump |
| Humid outdoor air | Musty smell, sweating pipes in summer | Dehumidifier, keep windows shut on humid days |
| Vapor through concrete | Damp under a plastic test sheet | Vapor barrier, foam board, sealer |
| Plumbing and appliances | Local stains | Repair leaks, vent the dryer outside |
Common questions
What size dehumidifier do I need for my basement?
A moderately damp 1,000 sq ft basement needs about 14 pints/day on the AHAM chart; GE puts it in its 22-pint class. Wetter or larger basements need more.
Why do the two charts give different numbers?
AHAM lists the moisture to remove each day; GE lists which of its rated models covers an area. Pick the larger result if they disagree.
Related calculators
Sources
- https://blog.directenergy.com/shopping-dehumidifier/
- https://products.geappliances.com/appliance/gea-support-search-content?contentId=34664
- https://www.epa.gov/node/78417