howardrichman
Senior Member
I'm installing several bath fan vents using a Fantech dual vent remote fan using 6" ducting, and two 110 cfm Panasonic units using 4" venting, multiple switching in two bathrooms. I'm not sure if two 4" pipes in one 6" roof vent will open the flapper if one 4" is pushing air. I'm also told there's a building code requirement to install a 8 R rating insulated pipe from these vents directed to the roof. Is hard pipe, aluminum soft, or ridged flex still permissible even though it doesn't meet r value requirements?
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