Bathroom Light and Ventilation

Bathroom Light and Ventilation

1. Provide outdoor light and ventilation to bathrooms, toilet rooms, and similar areas using windows or doors containing glazing. Provide a total glazing area of at least () 3 square feet

with atleast () 1 ½ square feet operable. Open the glazing directly on to a street, public alley, or on to a yard or court located on the same lot.

2. You may replace the glazing with artificial light and a mechanical exhaust system that complies with Chapter 15. Refer to Chapter 15 for information about exhaust

requirements when using whole-house mechanical ventilation. Provide at least () 50 cfm intermittent (switched) exhaust or at least () 20 cfm continuous exhaust when using

a local exhaust fan.

3. Discharge bathroom and toilet room ventilation fan exhaust directly outdoors. Discharging a ventilation fan exhaust duct into or toward an attic, soffit, or crawl space vent does

not comply with this provision. The duct must discharge directly outdoors.

4. Do not recirculate air from bathrooms within a residence or into another residence.

5. Provide an automatic or gravity operated damper for exhaust systems that will close the damper when the system is not operating.

Bathroom Ventilation Best Practice

Provide bathroom exhaust fans or a whole-house mechanical ventilation system in all bathrooms, even those with operable windows. Mechanical ventilation improves air quality and

helps maintain proper moisture levels in the home. Excess moisture can migrate into wall and floor cavities and into the attic. This moisture can damage materials and provide

moisture for fungal growth.