Basement Humidity Level What is Ideal?

By Terry Schutz, Feb 28, 2023

The basement humidity level should vary between 30% in winter and 50% in summer. – 25% is too low and can cause skin conditions and peeling paint. – Over 60% is considered too high and can lead to breathing problems, mildew, and fungal growth.

Knowing the difference between humidity and relative humidity (RH) helps us understand why ideal readings differ between summer and winter. – Humidity is the amount of water vapor in the air. – Relative humidity is the amount of moisture the air contains relative to the maximum amount it could contain at a given temperature.

You should keep summer humidity levels as close to 50% as possible, with an upper limit of 60%. If your humidity is too high in the summer, here’s what will happen in your basement: – Increased Mold and Fungus GrowthTermitesDust Mites

The ideal winter humidity level is around 30%, with an upper limit of 40% and a lower limit of 25%. RH that is consistently lower leads to too little moisture in the air, causing the following problems: – RespiratoryScalpSkin

Seal any gaps and cracks in your foundation walls, floors, and window frames to stop the moisture in your basement. Make sure that your landscaping is sloped away from the house. Buy a dehumidifier to remove moisture from the basement air.

Removing Excess Basement Humidity