A crawl space dehumidifier keeps the air under your home dry after the vents are sealed. Cobb sizes each unit to the crawl space: about 70 pints a day for up to 1,500 sq ft, 100 pints for up to 2,500 sq ft and 130 pints for larger homes. Vent sealing plus a dehumidifier typically runs $3,000–$4,000 on its own and is included in every encapsulation package.
Why a household dehumidifier won't cut it
Store-bought units aren't built for cold, dusty crawl spaces, they fill a bucket that nobody empties, and they're undersized for a whole crawl space. A crawl space dehumidifier is built to run in those conditions and drains automatically.
Sizing chart
| Crawl space size | Dehumidifier | Vents sealed (typical) |
|---|---|---|
| Up to 1,500 sq ft | 70 pints/day | Up to 15 |
| 1,500–2,500 sq ft | 100 pints/day | Up to 20 |
| Over 2,500 sq ft | 130 pints/day | Up to 25 |
Extra vents beyond those counts are sealed at a small added cost per vent. Your inspection confirms the size.
Seal first, then dehumidify
A dehumidifier in a crawl space with open vents is trying to dry the outdoors. We always seal the foundation vents with foam board when we install a unit. Sapphire packages add Wi-Fi monitoring so you can check the humidity from your phone.
What healthy looks like
A sealed, dehumidified crawl space holds steady at 50–55% relative humidity. A typical vented Upstate crawl space in summer reads closer to 75–80%.
Where we work
We serve homeowners within about an hour of our Anderson shop, including Anderson, Greenville, Clemson, Easley, Seneca, Pickens, Powdersville, Greenwood and nearby towns in South Carolina and Northeast Georgia.