Effective bathroom ventilation is important for reasons including excessive humidity, potential mold contamination, odor control, and basic comfort issues. Bathrooms are generally the wettest room in the house and may affect general air quality throughout the entire home. In many locales, building codes today require some form of mechanical bathroom ventilation — beyond simply opening a window — to prevent these issues.
Bathroom exhaust fans are the most common method to ventilate bathrooms. Installed in the bathroom ceiling or in a bathroom wall, these electric units remove water vapor and odors rapidly, before damage or mold contamination is triggered. Here are some basics of bathroom fans:
CFM capacity. The air-moving capacity of a bathroom fan is rated by its cubic-feet-per-minute (CFM) capacity. While the proper size can vary according to the number and size of bathroom fixtures like the bathtub, shower, and sinks; generally speaking, a bathroom exhaust fan should provide at least 1 CFM of ventilation per square foot of bathroom size (length x width.)
Exterior venting. Venting bathroom fans directly into the attic is a terrible option. Moist bathroom air in the attic space triggers toxic mold growth and accelerates deterioration of exposed wooden attic structure. Bathroom fans should be connected to a dedicated duct that extends all the way to the exterior of the house. Vent fans installed in the wall must likewise exhaust outside, not into the wall cavity.
Timer operation. A bathroom fan should run long enough to effectively exhaust water vapor and odors, but not too long, so as to avoid excessive loss of heat or cooling as well as wasted electricity. Bathroom fans should be connected to a timer switch to automatically shut off the unit after a preset duration. For best results, the fan should run for at least 15 minutes following a shower or bathing.
Safety factors. Bathroom fans should be wired to a GFCI (Ground Fault Circuit Interrupter) circuit to prevent electrical hazards in the wet environment.
For more about the benefits of exhaust fans for adequate bathroom ventilation, contact the air-quality professionals at Air Assurance.