rick15752
New Member
Hi everyone,
I am remodeling my home in the California Bay Area (mild climate) and must install exhaust fans in all bathrooms, despite the fact that there are windows in each bathroom. I have a call into the local building inspector and I'm waiting to hear back about requirements, but have not had a return call. Maybe someone here can help me figure this out.
Questions:
1. What kind of ducting is best? I've seen rigid galvanized, rigid aluminum and flex aluminum. I think the rigid is best because it is smooth and there will be better air movement than the flex, which has ridges. At the big box store, galvanized comes in 5' sections and aluminum comes in 2' or 3' sections. My laundry room had a 3" uninsulated aluminum flex for it's exhaust fan. I'll be replacing that too.
2. What is code as far as where to terminate the wall cap from a door or window? I've seen 3' on other forums. The concern is exhausting the bad air outside only to have it return through an open window or door. Is the 3' from the actual opening (vent portion) of the window? Or from any part of the window? My concern is that the 1st floor bathroom is quite small and I may not be able to stay 3' away from the window unless I use a few elbows. Also, the exhaust fan would be 2' - 3' from the exterior wall, where a window happens to be. So, the duct would have to 90 in a few places to avoid being too close the window.
3. The two upstairs bathrooms are back to back and I would like to have just one wall cap rather than two. This would mean running two separate ducts to the gable wall in the attic and then into a wye that would connect to a wall cap. Maybe the wye and wall cap would be larger than the 4" ducts to accommodate the two fans in the event they are running at the same time. Is this a bad idea?
Hope someone can help.
Thanks.
Rick
I am remodeling my home in the California Bay Area (mild climate) and must install exhaust fans in all bathrooms, despite the fact that there are windows in each bathroom. I have a call into the local building inspector and I'm waiting to hear back about requirements, but have not had a return call. Maybe someone here can help me figure this out.
Questions:
1. What kind of ducting is best? I've seen rigid galvanized, rigid aluminum and flex aluminum. I think the rigid is best because it is smooth and there will be better air movement than the flex, which has ridges. At the big box store, galvanized comes in 5' sections and aluminum comes in 2' or 3' sections. My laundry room had a 3" uninsulated aluminum flex for it's exhaust fan. I'll be replacing that too.
2. What is code as far as where to terminate the wall cap from a door or window? I've seen 3' on other forums. The concern is exhausting the bad air outside only to have it return through an open window or door. Is the 3' from the actual opening (vent portion) of the window? Or from any part of the window? My concern is that the 1st floor bathroom is quite small and I may not be able to stay 3' away from the window unless I use a few elbows. Also, the exhaust fan would be 2' - 3' from the exterior wall, where a window happens to be. So, the duct would have to 90 in a few places to avoid being too close the window.
3. The two upstairs bathrooms are back to back and I would like to have just one wall cap rather than two. This would mean running two separate ducts to the gable wall in the attic and then into a wye that would connect to a wall cap. Maybe the wye and wall cap would be larger than the 4" ducts to accommodate the two fans in the event they are running at the same time. Is this a bad idea?
Hope someone can help.
Thanks.
Rick
