I'm currently remodeling my upstairs bathroom and replaced the old vent fan, which was small but still functional at 130 CFM. I swapped it out for a fan/light combo that has a lower rating of 100 CFM. This bathroom is frequently used by my four kids, so it gets a lot of traffic. While working in the attic, I noticed that the 4" flexible vent felt unusually heavy, and upon lifting it, I discovered it had collected water. I managed to dump most of the water from the outside vent, which seems abnormal. What could be causing this accumulation? The flexible vent is insulated and has a louvered vent on the outside that opens when the fan is on. The vent exits through the wall instead of the roof. Should I be concerned about the insulation or the setup?
2 Answers
It sounds like you might have some angles in the venting that are creating a trap for condensation. If there are peaks and valleys in the duct, that could definitely lead to water buildup. Ideally, the vent should have a slight downward slope to help any moisture escape. You might want to consider adjusting the height right off the fan to ensure everything flows downhill from there. That could really help in preventing water from collecting again.
Exactly, even minor adjustments can make a big difference!
There could be a few reasons for the water accumulation. First, if there's heavy rain, it might be blowing past the louvers and leaking down into the vent. Also, if you've got a lot of steam from hot showers, that moisture might be condensing in a low spot of the duct and causing droplets to form. Try to keep the fan running longer after showers—maybe even provide some support to the vent to avoid any dips that could trap water. That might help too!
Good point! Keeping the fan on can really help reduce moisture levels.
Yeah, I agree! Support those ducts and run the fan longer.
Definitely check the slopes! It'll help with airflow too.