Select the right Vent
By rule of thumb, the air inside your bathroom should be circulated eight times every 60 minutes. If you have a higher ceiliing than a usual batroom a slightly stronger fan will be needed.If you are not sure about what size fan you need, there are online bathroom vent fan calculators that can help you out.
Always Vent Outside
Regardless of the venting option you pick, you should always vent the bathroom outdoors, very often people let theres sift out into the ceiling or the attic. This can cause a build up of moisture in the air and cause mildew in yiur roof and weaken the wooden support in your roof. Generally speaking, there are two different methods of venting a bathroom fan: sidewall and roof. A sidewall vent is most ideal when the bathroom is on the first floor.
Choosing the Correct Place
It's best to install the vent somewhere between the toilet and the shower. It is recommended to avoid any joints or studs and place in between ceiling studs. Make sure that the vent is tightly seured so that it does not accidentally fall when in use.