Hansberger Refrigeration Blog: Your AC Repair Resource

Your Guide to Smart Bathroom Ventilation in Your Home

Adequate home bathroom ventilation doesn’t happen by itself. The bathroom is the source of high humidity and odors enclosed in a very limited space. The high humidity accumulating in bathrooms can deteriorate building materials and spawn mold growth on surfaces. Chronic moisture also penetrates into structural spaces within walls and ceilings and triggers hidden damage and mold. Bathroom moisture and odors typically don’t stay in the bathroom and may migrate into other living spaces.

It’s important to note that many homes were constructed when building codes only required a small window for bathroom ventilation. Today, we know that adequate ventilation requires a dedicated bathroom exhaust fan. Here are some guidelines for exhaust fan ventilation in your bathroom.

  • The exhaust fan should be installed in the ceiling or in the wall. The fan must vent moist air all the way to the outside of the house through a dedicated vent duct. Exhausting moist bathroom air into the attic is very destructive to wooden attic structures and insulation.
  • A bathroom exhaust fan should be sized to the room dimensions. In a typical installation, the exhaust fan should be rated to remove one CFM (cubic foot per minute) of air per square foot of bathroom floor area. For example, a bathroom floor measuring 7 feet by 10 feet has a square footage of 70 feet. Therefore, the exhaust fan should have a rating of at least 70 CFM.
  • Simply operating the fan while the bathroom is occupied is not enough.  The fan should be actuated by a timer to run for a specified duration. Most experts recommend that the fan timer should keep the fan running for 20 minutes to completely exhaust the room, then turn off automatically.
  • Once or twice a year, turn off power to the fan and remove the fan vent cover. Wash the cover in hot soapy water and wipe down fan blades to remove dust and dirt residue. Reinstall the fan cover. This will also help your bathroom ventilation.

For more info about adequate bathroom ventilation, contact the air-quality experts at Hansberger Refrigeration and Electric Company.