Bathroom Exhaust Fans | GreenBuildingAdvisor.com
Older homes often lack bathroom exhaust fans . In the old days, if the bathroom was smelly or steamy, you were supposed to open a window to air it out. This isn’t a very logical ventilation method , especially when temperatures are below zero, or when the weather is 90°F and humid. Yet this time-honored method of bathroom ventilation is still enshrined in our building codes. According to the 2009 International Residential Code (sections R303.3 and M1507.3), a bathroom with an operable window does not need to have a bath exhaust fan . Why do we need exhaust fans? In spite of the code’s archaic loophole, builders should install an exhaust fan in every bathroom or toilet room — even when the bathroom has a window. A bath exhaust fan can perform several functions: It can exhaust smelly air , allowing fresher air to enter the bathroom. It can exhaust humid air , allowing dryer air to enter the bathroom. When operated for 24 hours per day or when controlled by a timer, it can act (in so...