Adding hvac duct work to bathrooms

[Danita Morris]

Rehabbing a home and not sure if it is necessary to add hvac duct work to bathrooms when there is already duct work throughout the rest of the house except the 2 bathrooms. I don't know if I want to take on that expense unless it is absolutely necessary. The house is a 3BR/2BA - 3 level row home in Baltimore, MD.

[Emilio Ramirez]

exhaust ventilation from a bathroom is generally required by code, although this varies by state and municipality. This can typically be accomplished by installing an operable window in dwellings of 4 units or less. Again this depends on your municipality.

If you don't have an operable window then you are required to install mechanical ventilation (exhaust fan and ductwork to exterior). This type of work generally requires a permit.

Depending on your climate, you may want to install an exhaust fan anyways.(Do you leave the window open after a shower in maryland in february?) Older bathrooms with drywall or greenboard are more prone to mold problems and would benefit from mechanical ventilation. The exhaust system needs to be seperate from the forced air system.