# Condensation on fresh air intake ducting - Major dripping



## Xeno (Jan 12, 2014)

Hey there,

Been having a condensation issue that I was hoping someone could help me with.

I have some 4" uninsulated duct that brings fresh air to my furnace. In the winter I find that it drips tons of water into the heated room that it passes through to get to the furnace. I have attempted to insulate it with the fiberglass kits that you wrap around it that are available at most hardware stores but the insulation just ends up getting soaked. 

At this point I can only think of two options,...

1. Add some sort of in-line heating element to warm the air as it enters the duct but all the heaters of this type I've seen seem to be VERY expensive and are meant to actually heat rather then just warm incoming air.

2. try and insulate the duct with rigid expanding foam gap & crack filler.

All help and suggestions are appreciated!


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## beenthere (Mar 5, 2009)

Did the insulation you wrapped it with have a vapor barrier? If not, you used the wrong insulation. Should have been foil faced duct wrap.


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## TXACguy (Jan 12, 2014)

*More Insulation..*

I don't know what the delta T is form the outside temp to the inside temp, but you must be in a really cold climate. You should be insulating the 4" line with a Good Foil back insulation. I would opt for the 2" (professional choice) and maybe wrap it twice.

The Home depot/ Lowes insulation is not the best. Contact one of your local HVAC guys and get him to install it, stapled and taped. That should do the trick.


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