Hey everyone! I'm in the middle of renovating my basement and adding a bathroom, but I've run into a problem with the exhaust vent. I installed a new ceiling fan and connected it with a 4-inch duct that leads outside. The setup involves a bendy 2-3 feet flexible duct, about 15 feet of rigid duct, and goes through the rim joist and a cantilever. After I closed up the cantilever section with insulation, I noticed a surprising amount of water pooling in the flexible duct. Has this happened to anyone else? Is it due to condensation since everything was exposed for a bit? Also, I'm wondering if I should have insulated the entire duct system. Would that just end up bringing more hot and humid air back to the fan? Thanks for any advice!
8 Answers
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Have you been using the fan? If it’s running and pulling moisture from the bathroom, it might just be trapping that moisture inside the ductwork if there's not enough airflow to ventilate it. If the fan hasn't been used much and the rigid duct is in an air-conditioned space, humid air might be entering from outside and condensing inside the duct. In this case, insulating the ducting would definitely help! Also, be careful—make sure you didn’t accidentally puncture any water supply lines along the way!
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The renovation isn’t done. The fan has not been run much other than to test.