iano Posted March 30, 2017 Report Share Posted March 30, 2017 Hello, I'm looking to add in a ventilation fan to the bathroom, ideally, one that activates a minute or so after that light has been turned on. The problem is that the only practicable place to put the external vent in is the gable wall, which would be c. 3m from the bathroom. What kind of fan and ducting should I use? The attic is cold, so I'm looking to avoid having the steam condense in the pipe and rancid water pooling, creating a smell. Thanks! Quote Link to comment Share on other sites More sharing options...
bruno22rf Posted March 30, 2017 Report Share Posted March 30, 2017 Ours uses a standard waste pipe of about 110 dia - we had to use tape to seal the fan to the pipe as the fan outlet was about 105 but it works fine - ours runs about 2 metres and our builder put a slight drop in the pipework to the wall just incase of the steam condensing - but we have had no issues at all in the 2 years since it was fitted. We have 4 downlighters in the bathroom with one being over the Shower cubicle - this one has a separate touch switch that also starts the extractor fan so you don't have to have all 4 lights on when showering during the day - the extractor is also directly above the shower cubicle. Buy the biggest fan you can get (within reason!!) - noise is similar no matter how big they are and most of the noise is from the outside vent. Quote Link to comment Share on other sites More sharing options...
Old Boggy Posted March 30, 2017 Report Share Posted March 30, 2017 For that length of ducting and to overcome the resistance you need a centrifugal fan as opposed to an axial one. If possible a slight fall to the outside grille would prevent any internal condensation running back into the fan. If possible you could also insulate the ducting to prevent any condensation on the outside of the duct. As said 100mm soil pipe is ideal and would prevent any sagging. Hope that this helps. OB Quote Link to comment Share on other sites More sharing options...
Yellow Bear Posted March 30, 2017 Report Share Posted March 30, 2017 Also ensure that the fan is as close to the discharge as is possible to avoid leakage discharge within the building. The type of fan is immaterial as at the size you require there is little difference in performance. The importance is volume to resistance ratio X l/s @ y Pa for a long run you need higher Pa. Quote Link to comment Share on other sites More sharing options...
Rst1990 Posted March 30, 2017 Report Share Posted March 30, 2017 Best advice would be to vent it straight through the roof. Quote Link to comment Share on other sites More sharing options...
iano Posted March 30, 2017 Author Report Share Posted March 30, 2017 Best advice would be to vent it straight through the roof. I really don't want the hassle of messing around with the roof. Also - you are still probably talking a 2m distance anyway. Quote Link to comment Share on other sites More sharing options...
Rst1990 Posted March 30, 2017 Report Share Posted March 30, 2017 I really don't want the hassle of messing around with the roof. Also - you are still probably talking a 2m distance anyway. But it would be vertical, a roofing contractor would be able to help. It would be the best way, but sometimes it's not the way you can do it, I understand. Quote Link to comment Share on other sites More sharing options...
Old Boggy Posted March 30, 2017 Report Share Posted March 30, 2017 Also ensure that the fan is as close to the discharge as is possible to avoid leakage discharge within the building. The type of fan is immaterial as at the size you require there is little difference in performance. The importance is volume to resistance ratio X l/s @ y Pa for a long run you need higher Pa. Sorry I stand corrected suggesting a centrifugal fan. They would only be necessary if using rectangular flat duct to overcome the resistance. An axial fan would be OK providing it gives the necessary power to overcome the resistance as pointed out correctly by Yellow Bear. OB Quote Link to comment Share on other sites More sharing options...
figgy Posted March 30, 2017 Report Share Posted March 30, 2017 (edited) Buy an Eviro Vent silent 100mm fan it has a run on timer you set and will pump easily more than 3m. As can be seen on you tube. I have them all over the house in toilets and bathrooms. https://m.youtube.com/watch?v=TuYGPG4_LxU Edited March 30, 2017 by figgy Quote Link to comment Share on other sites More sharing options...
vampire Posted March 30, 2017 Report Share Posted March 30, 2017 Ours uses a standard waste pipe of about 110 dia - we had to use tape to seal the fan to the pipe as the fan outlet was about 105 but it works fine - ours runs about 2 metres and our builder put a slight drop in the pipework to the wall just incase of the steam condensing - but we have had no issues at all in the 2 years since it was fitted. We have 4 downlighters in the bathroom with one being over the Shower cubicle - this one has a separate touch switch that also starts the extractor fan so you don't have to have all 4 lights on when showering during the day - the extractor is also directly above the shower cubicle. Buy the biggest fan you can get (within reason!!) - noise is similar no matter how big they are and most of the noise is from the outside vent. Exactly what said here. When i do a bathroom the sparks always put fan on switch with shower light and not the main light and get the most powerful one. Quote Link to comment Share on other sites More sharing options...
Grandalf Posted March 30, 2017 Report Share Posted March 30, 2017 Fit it in the window glass. Quote Link to comment Share on other sites More sharing options...
billytheghillie Posted March 30, 2017 Report Share Posted March 30, 2017 Best advice would be to vent it straight through the roof. that's where mine went. Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted March 30, 2017 Report Share Posted March 30, 2017 Buy an Eviro Vent silent 100mm fan it has a run on timer you set and will pump easily more than 3m. As can be seen on you tube. I have them all over the house in toilets and bathrooms. https://m.youtube.com/watch?v=TuYGPG4_LxU Our only toilet is in the only bathroom we have unless you take into account when I pee in the grate outside but this is naturaly aspirated Quote Link to comment Share on other sites More sharing options...
amateur Posted March 30, 2017 Report Share Posted March 30, 2017 I bought a Ventaxia Solo Plus TM with timer and PIR from Wiggum on here. That operates automatically as you step in to the bathroom (PIR) and runs for as long as you set it for.Ours outlets into the eaves with 3m of 100mm trunking. It is very quiet, shifts a lot of air and there is a new one on eBay £40 buy it now Quote Link to comment Share on other sites More sharing options...
stephensedgwick Posted April 2, 2017 Report Share Posted April 2, 2017 Exactly what said here. When i do a bathroom the sparks always put fan on switch with shower light and not the main light and get the most powerful one. so are you saying you don't have the fan working if you are running the bath Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.