Bathroom Fan Ventilation

[farmboy101]

Hi Experts.....I have just done a complete bathroom renovation and put in a new bathroom fan. Everything works great except the fan. It drips water like crazy. So we insulated the metal housing and put a plastic dome and tucted taped it to seal the cold away from it. We also put a few extra bats of insulation on top of all the fan housing and duct venting which incidently is that insulated metal ducting. So we have done all things we thought could be causing the condensation. The steam hitting the cold metal housing and driping back down...?? It would seem that a fan with a plastic housing would be a better choice. We have gone to the box stores and can't seem to find a brand that comes with a non metal housing??? Have any of you guys/gals come across this sort of thing and what brand of fan would you suggest?? Thanks very much all....

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[Joe Steam]

I was going to say to move south or take cold showers.... I think you are working against physics, and even plastic may get cold and condense the humid air in the bathroom.
How about turning on the fan some minutes before turning on the water for a shower, this may heat up the duct enough to reduce the condensation??

[Thatguy]

Maybe you could put heat tape on the duct but I don't know that anyone does this.
For troubleshooting purposes only, you might temporarily put a small lamp, 10 W or so @ 12 V, in the duct or fan housing. At least it will give you some idea of how many BTU/hr you need to stop this problem.