The potential for mold is enhanced by the condensation of excess humidity–usually the result of poor shower area ventilation. To begin, make sure the fan is properly sized. A good general rule for bathrooms with 8’ ceiling heights is to allow at least 1 cubic foot per minute (CFM) of ventilation for every square foot of room size for bathrooms under 100 square feet. For larger rooms, the recommendation is based on adding 50 CFM for each toilet, bathtub or shower and 100 CFM for jetted tubs. Generally speaking, the larger the CFM rating of the fan, the faster it will take care of any issues. To ensure that everyone in your home uses the fan, selecting a quiet model is always recommended. The NuTone QT Series offers models ranging up to 150 CFM with a range of quiet sound ratings (measured in Sones). Most are ENERGY STAR® Qualified which will save on electric bills, and are offered in either fan only configurations or with bright lighting and nightlights. For the best solution, select a NuTone humidity sensing fan that will turn ON and OFF automatically whenever humidity becomes a problem.