Hello,

I moved into a house a few years ago and installed a bathroom vent. It previously functioned with just a window, but it would create a hurricane with the shower curtain when left open while showering so I decided to try upgrading to a venting system.

Venting works fine but every time I turn on the vent the upstairs bedrooms get filled with attic dust, has an odd smell and makes my lungs and eyes super irritated. If I crack open any window in the house and run the shower vent I have no issues. I also found out that running a window fan in the basement will suck attic dust into the upstair bedrooms if I dont crack a window open.

Is there a way to control where the bathroom fan sucks in air? At the moment Ive just been cracking open the bathroom window when the vent is running and Ive had zero issues. However 2 times this year I accidentally ran the fan without cracking open a window and had to vacuum/air purifier the bedrooms.

I live in a 2 story cape cod with kneewalls. I ran a window fan in the bedrooms with the door closed and the air/dust seems to be sucking in from where the wall meets the floor. The bedroom and kneewall attic share the same floor boards, its just separated by a wall. The walls are batt insulation while the floor is some type of cotton ball like blown fiberglass insulation.