# crawl space venting and HE furnace?



## bcbud3 (Jan 22, 2010)

I am in Vancouver BC, Canada. I just had a new HE furnace installed. The installer ran 2 pvc pipes out the side of my house. Is there a cap that could be put over the ends for looks? My crawl space already has vents, are they needed? When i first moved in, the crawls space smelled fine. I put up styrofoam sheating around the walls and after that the crawlspace became a little musty. What would be best here?


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## operagost (Jan 8, 2010)

I can't answer the furnace venting question (that might be best for the HVAC forum), but did you close off your crawlspace vents? And what does your crawlspace floor look like?


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## bcbud3 (Jan 22, 2010)

I had left the vents open and then closed them for winter. floor is rocky with plastic over top


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## operagost (Jan 8, 2010)

It's musty because the humidity level is high and allowing mold to grow. Again, I'm not an expert, but there may be a breach in your vapor barrier (the plastic). I don't know if the new furnace has anything to do with it.

Hopefully someone has a suggestion for the vents.


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## Greg Mitchell (Mar 8, 2010)

*Crawlspace odors*

The crawlspace should be sealed and insulated. I own a specialized crawlspace improvement company called "Crawlpaces.com" in Chicago (originally I am from Vancouver). I have been creating healthy, conditioned crawlspaces for over 10 years. Your best answer to the musty air is to create mini-basement and seal off the gravel/rock/dirt with a concrete floor. Use a good vapor barrier and pump in 3-4 inches of concrete. Insulating with spray foam on the foundation is ideal for this area as well, and you will never have a problem with mold or humidity again. Put in a dehumidifier for an added precaution, but it likely wont run often. Go to the site CRAWLSPACES.COM to learn more - and send me an email - I'll be in Vancouver end of March if you would like to show me the crawlspace for further ideas.


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## Greg Mitchell (Mar 8, 2010)

*HVAC in crawlspace*

The HVAC unit sounds like a 90 percent efficient, so you do not need any make up air (the 2 PVC pipes are combustion air and exhaust). The odor is due to weak vapor barrier, which will likely never be sealed properly. The smell in the crawl, to be sure, is not at all related to the HVAC system. It is also correct to stop outside air venting of the crawlspace. Another good idea is to include a supply vent from your ductwork and push conditioned air into the space as well, which creates the mini - basement effect and will warm your floors in the winter.
GM


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## Michael Thomas (Jan 27, 2008)

Where is the furnace condensate draining to?


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## bcbud3 (Jan 22, 2010)

the furnace condensate is draining to a pump which in turn runs to the main vent stack/drain.


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## Michael Thomas (Jan 27, 2008)

Good. I often see the condensate spilling into the crawl space.


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## bcbud3 (Jan 22, 2010)

Greg Mitchell said:


> The HVAC unit sounds like a 90 percent efficient, so you do not need any make up air (the 2 PVC pipes are combustion air and exhaust). The odor is due to weak vapor barrier, which will likely never be sealed properly. The smell in the crawl, to be sure, is not at all related to the HVAC system. It is also correct to stop outside air venting of the crawlspace. Another good idea is to include a supply vent from your ductwork and push conditioned air into the space as well, which creates the mini - basement effect and will warm your floors in the winter.
> GM



When you say "include a supply vent from your ductwork and push conditioned air into the space as well, which creates the mini - basement effect and will warm your floors in the winter." do you mean to heat the crawl space as well?


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## bcbud3 (Jan 22, 2010)

Greg Mitchell said:


> The HVAC unit sounds like a 90 percent efficient, so you do not need any make up air (the 2 PVC pipes are combustion air and exhaust). The odor is due to weak vapor barrier, which will likely never be sealed properly. The smell in the crawl, to be sure, is not at all related to the HVAC system. It is also correct to stop outside air venting of the crawlspace. Another good idea is to include a supply vent from your ductwork and push conditioned air into the space as well, which creates the mini - basement effect and will warm your floors in the winter.
> GM



When you say "include a supply vent from your ductwork and push conditioned air into the space as well, which creates the mini - basement effect and will warm your floors in the winter." do you mean to heat the crawl space as well?


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