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Dehumidifier size for 1,500 square feet
Two published charts answer the question in different ways. The AHAM chart gives the daily moisture removal needed for a space; GE's chart says which of its current 22, 35 and 50-pint models covers a given area. For 1,500 sq ft the answers by dampness level are:
| Condition | AHAM capacity | GE model class |
|---|---|---|
| Moderately damp | 18 pints/day | 35 pint |
| Very damp | 22 pints/day | 50 pint |
| Wet | 26 pints/day | 50 pint |
| Extremely wet | 30 pints/day | 50 pint |
A basement that is only musty in summer needs about 18 pints a day on the AHAM chart. If water seeps through the walls, plan on about 26, and fix the leak as well: a dehumidifier removes moisture from the air, not water coming through the foundation.
Ceiling height changes the answer
Both charts assume an 8-ft ceiling. GE says to add 25% to the area for a 10-ft ceiling, which is the same as scaling area by height ÷ 8. A moderately damp 1,500 sq ft basement works out like this:
| Ceiling | Area to use | AHAM | GE class |
|---|---|---|---|
| 7 ft | 1,312 sq ft | 16 pt | 35 pint |
| 8 ft | 1,500 sq ft | 18 pt | 35 pint |
| 9 ft | 1,688 sq ft | 20 pt | 35 pint |
| 10 ft | 1,875 sq ft | 21 pt | 35 pint |
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.
The full charts
| 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.
Common questions
What size dehumidifier do I need for 1,500 square feet?
For a moderately damp basement, about 18 pints per day on the AHAM chart; GE's chart puts it in the 35 pint class.
Is a bigger dehumidifier better?
An oversized unit reaches the set point sooner and cycles off. Size from the chart for your dampness level and round up to the next model if you are between sizes.
What humidity should I set it to?
The EPA recommends keeping indoor humidity below 60%, ideally between 30% and 50%.
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