Adequate bathroom ventilation doesn’t happen by itself. Elevated humidity in the bathroom is more than the inconvenience of fogged mirrors after a hot shower. Condensation forming on all surfaces promotes toxic mold growth, mildew, and bacteria. Chronic bathroom moisture also degrades paint and seeps into wall cavities and the ceiling, deteriorating drywall. Moreover, high humidity doesn’t stay in the bathroom — it can affect indoor air quality throughout the house.

A bathroom ventilation fan is standard equipment to effectively exhaust water vapor and odors, as well as rapidly dry wet bathroom surfaces after use. Choosing the appropriate unit and installing it correctly are jobs for a trained professional who is experienced and qualified to take all factors into consideration. Here are the basics:

• Sizing it right. Sizing refers to matching the air-moving capacity of an exhaust fan to the requirements of the specific room. In a standard bathroom, a fan should move 1 CFM (cubic feet per minute) of air per square foot of room area. However, the sizing calculation can vary substantially due to additional floor space or added fixtures that may generate extra water vapor such as a whirlpool bath or sauna.
• Duct installation. Moisture-laden bathroom air exhausted directly into the attic causes mold growth, ruins insulation and rots wooden structural components. A bathroom vent fan installed in the ceiling must exhaust air through a dedicated duct sized to accommodate fan output and routed all the way to the exterior of the house.
• Timer operation. An exhaust fan needs to continue running for a certain period — usually 15 or 20 minutes — after the bathroom is utilized in order to effectively remove water vapor and odors. Installation of a timer switch to automatically shut the fan off after the required interval saves energy and ensures adequate humidity removal, as well as the drying of bathroom surfaces.
• Safety. Any electrical device installed in an environment where water and high humidity are present should be wired to a GFCI (Ground Fault Circuit Interrupter) circuit for protection against shock hazards and short circuits.

If you have questions about your indoor air quality contact the professionals at Jackson & Sons. Serving homes and businesses in Eastern North Carolina since 1974.