GO FROM THIS…
By nature cool damp air collects at the lowest level of a structure, basement or crawl space. When you smell a musty odor in your basement it does not necessarily mean you have mold growth. The musty odor you smell is microbial mold odor that is in the air and can lead to mold growth on surfaces.
Basement and crawl spaces have the least amount of air flow in our homes. It is important to have air movement in these areas. Dehumidifiers help with moisture control but do nothing to move the stagnate air. I recommended some kind of constant air flow.
This can be achieved several ways. You can program your furnace, if you have forced air, to have the fan run. This will help circulate air if you have the duct work in place in these areas. Many homes are not set up to create the proper air flow. At MMCS we install fresh air exchange units that pull the warmer dryer air from the upper levels down into the lower level and circulate the stagnant air to the outside.