by Mr White »
Sat Jan 27, 2018 1:49 pm
If you are asking can you connect another fan to the same supply / junction box then yes you can, but it will come on at the same time as the existing fan.
If you are saying you want to add an additional fan because the original is not "doing the job" there are a couple of other things you can do.
1) Change the existing fan to a bigger / faster fan.
2) Check air flow.
Something often forgot with an extractor fan is the fact it can only extract what is replaced. So if the fan is in a typical bathroom the door will be shut, there is a quick and simple test to check. Run the shower / bath with the fan running, but the door shut for about 5 minutes, now open the door, if all the steam "disappears" within seconds it means that the fan is doing its job, BUT there is not enough vents to let air IN to the bathroom for the fan to extract, so no matter how big a fan you put in, it will not work unless you add more air vents to allow air INTO the room.