Bathroom Vent Fan Question

This winter, I redid our master bath. Part of that included upsizing the vent fan, and one with a heater. When I installed the new unit, hooked it up to the existing discharge, same routing. Previous unit did not have heat.
Now, when ambient temps are 25 or below, water drips back down the unit. I went in the attic, felt the plastic dryer vent discharge hose, it had ice in it. Unhooked it, thawed it out, reinstalled . It went pretty much straight up. This time, I angled it more. It happened again.
See attached photo.

Attachment 482245






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You are pumping more warm moist air with a higher capacity fan. You need to insulate the exhaust tube to keep it from building condensation inside the tube. Easy fix. It should also be vented to the outdoors. Pumping moist air into your attic is a recipe for disaster, rotted plywood and/or mold will almost certainly be the result.

First of all, I wouldn't use that type of flex duct. That type drys out & cracks. I would use the insulated flex duct they use for hvac. Vent to outside & not into your attic. Looks like you could use some insulation in your attic also. Cover that fan up with insulation.

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Curly tail is wise. Listen to him on all counts. Insulate pipes to outside so you don’t rot your rafters

Spartannation on the money also.

I did as advised. Changed out the plastic junk for insulated duct, vented it out the gable ends. Put some extra insulation over the unit in the picture. Did the other main level fan as well. Other fan was adequately covered.
Part of the reason the insulation looks inadequate, I have been in that part of the attic, running camera cables, changing sewer vent pipe and the vent fan in question. Forgot about needing more insulation.
I’m going to price insulation, see what we do for it.
Thank you to all!! For the advice!!!!!


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