Humidity & Mold in Charleston
Charleston, South Carolina sits in a humid subtropical climate averaging 74% relative humidity. Here is what that means for your home — and the products that actually help.
Quick answer
In Charleston, keep indoor relative humidity between 30% and 50% (EPA guidance). A 30–35 pint dehumidifier covers most rooms up to 1,500 sq ft; a 50 pint unit with a continuous drain is better for basements. The most frequent local problems are coastal flooding, historic wood rot, salt-air corrosion.
Top moisture issues in Charleston
Best dehumidifiers for Charleston
More in South Carolina
Charleston humidity FAQ
What is the average indoor humidity in Charleston?
Charleston averages about 74% relative humidity (Humid subtropical climate). Keep indoor levels between 30% and 50% RH, as recommended by the EPA, to limit mold growth.
Why does mold grow so easily in Charleston homes?
The most common local drivers are: Coastal flooding, Historic wood rot, Salt-air corrosion. Mold needs moisture, an organic surface and stagnant air — controlling humidity removes the first condition.
What size dehumidifier do I need in Charleston?
For a damp room up to 1,500 sq ft in Charleston, a 30–35 pint unit is usually enough. For a wet basement or 2,000+ sq ft, choose a 50 pint model with a continuous drain hose.
