Can I run a dryer vent against a basement foundation wall?

[benze]

Hi,

I live in Montreal, Quebec, Canada, where winters are quite cold and severe. Temperatures here can be as low as -30F in winter. I'm not sure this counts as an HVAC question, but I think this forum is the closest match I can find.

I am installing a new dryer vent in my basement and in order to save as much space as possible, I'd like to run the vertical part of my vent in between my 2x4 studs directly against the foundation wall (a run of about 8'). The walls will be insulated with fiberglass (pink) and covered with a vapor barrier and drywall.

My concern is condensation. Is condensation around the exhaust pipe a worry? Do I have to ensure that my pipe runs on the inside of the insulated walls? Or do I need to use an insulated pipe? (ie: can I take a 4" pipe and insert it into a 5" pipe and line the space in between with fiberglass?)

Thanks for any suggestions!

Eric

[jadnashua]

If you don't seal the seams and joints in the duct, you could be putting moist air into that space and that would create a problem. It would depend somewhat on how far from the dryer that section of ducting is...the closer to the dryer, the hotter the air is. The output can be quite warm, so it probably wouldn't cool to the condensation point until it got outside. Only on the end of a cycle if it modulates the output is that likely to happen. I've never tried that, so I can't say with certainty. You might give the dryer manufacturer a call and seek their guidance. I'd probably consider aluminum duct rather than galvanized steel, just in case.

A 4" duct won't fit in a 2x4 stud wall...you'd need to switch to an oval configuration which would have more surface area, and cool things off more...

[Ian Gills]

The fiberglass insulation you intend to use should help to stop condensation. Without it you would have to worry.

[cacher_chick]

There could be problems in your plan regarding the insulation and vapor barrier. There is a great article here that you might find informative-
http://www.buildingscience.com/docum...lation-systems