Our basement has a musty smell. It is not wet and has never been wet and there is no evidence of moisture, condensation or mold. We have a dehumidifier running all the time. How can we get rid of the smell?
no evidence of moisture, condensation or mold
The evidence is the musty smell.
Check the actual relative humidity of the basement; it should be well under 50%.
If this is a finished basement and it is dry, the smell may be from mouldy materials that are hidden from view, such as insulation and framing. Our current home has exactly this problem--from the sleepers directly on the concrete under the finished floor. We keep the odour in check by running two dehumidifiers to keep it bone dry. (It's scheduled for demolition in a year, so there's no point stripping the basement and starting over.)