A client who had purchased a home noticed mold growing on furniture stored in their cellar as well as a musty smell when ever they were in the cellar.
Investigation: The home is a sixty year old house nicely maintained and very clean with new paint and floor finishes on the inside. The heating system is a gas fired forced hot water system. There is no air conditioning. Relative humidity readings showed a 25% higher reading in the cellar than the upstairs.
Analysis: High levels of moisture in the cellar ( above 75% R.H.) contributed to mold growth on stored items. The mold growth produced mold by-products that accumulated and caused a distinct musty odor.
Recommendations: Install an exhaust only fan in the cellar with vents from the upstairs providing make up air. This flushes out the musty air and replaces it with fresh clean air from upstairs. This will also tend to reduce the elevated levels of humidity in the cellar.
Results: A Humidex exhaust fan was installed and within one hour the “musty” odors were gone.