Is it possible to stop the stack effect (rising up of warm air causing dirty crawlspace air to be sucked into living area) by installing an exhaust fan in the crawlspace (obviously all vents are covered except the exhaust vent) and creating a negative air pressure?
Or would this just create a convection effect where in cooler part of the house, air migrates down into the crawlspace, and in warmer area of the house, air rises upwards and pulls the crawlspace air into the living area?
If air is leaking in one direction into the living area, installing a fan t o suck air out seems like it would be pulling air from the living space. I would get down there and start plugging holes and sealing gaps and maybe i nstall some sort of vapor barrier under the floor joists.
to suck air out seems like it would be pulling air from the living space. I would get down there and start plugging holes and sealing gaps and maybe install some sort of vapor barrier under the floor joists.
+1Must be some unusual construction or circumstances where this "dirty air" is somehow noticeable. And what makes it dirty?
Single dimensional thinking. No insulation on the ceiling of crawl space? Dirty air? Maybe Radon gas build up? I just got the Radon gas level in our basement after 6 months sample collection sent in. Way below UN or government set limit of safe level. We were told nothing needs to be done.
Why is the crawlspace vented into the living area in the first place?
first you want to seal the floor as well as possible to minimize air from the CS getting into the house.
Then putting an exhaust fan in the crawl space exhausting to the outside will help to prevent air flow from the CS to the house. But two bad things may happen. You may pull air from the house into the CS which would waste warm air. Also you may pull more radon up out of the ground.
So..
1) seal as best a possible between the house and the CS 2) vapor barrier on the ground to minimize moisture and radon into CS 3) small exhaust fan to the outside on the lee side of the prevailing wind 4) small opening on the opposite side to let some fresh air into the CS. You don't want the pressure to be too low in the CS, just low enough to minimize air from flowing from the CS into the house. M
Ditto. Dirty air? May be Radon gas? High level of this gas is major cause of lung cancer. I had our house basement Radon gas level checked and it is well below safety limit of 200Ml/m3.
trader_4 posted for all of us...
Farts and other odoriferous parts of his body.
Scott Lurndal posted for all of us...
"Dirty air" Can't you read? 8~)
No one here mentioned sealing any gaps/cracks in the highest ceilings in that place, plus the minimum insulation r-value for your area of the country. That, plus sealing the floor, will stop the up-drafts in a heartbeat.
Goody for you. There is no reason to think that what he calls dirty has radon in it. Radon is colorless, odorless, tasteless, and soundless. People don't notice it, so they don't consider it dirty.
I agree with those who thought the crawl space could be sealed from the rest of the house.
And iiuc you mostly called the crawlspace dirty, not so much its air. But for your specific questi>Is it possible to stop the stack effect (rising up of warm air causing
These days, "obviously" has become a very popular word. It's not obvious to me!! I'd leave one other basement to outside vent uncovered, at the opposite end of the house. Otherwise what you fear will indeed happen, and maybe anyhow.
I dont' think it would even have to be cooler if the air pressure in the crawl space is lower.
No, it won't create this. But you've said it already exists. Your plan would lessen it and maybe eliminate it. It would not increase it. And your plan is something you can do in the winter, while all the suggestions for sealing leaks seem best left for the spring or summer.
!!! But wait a second. Isn't the air in the crawl space colder than any of the air in the house? Is it really rising from the crawl space, or is it only a tiny whiff of the smell?
Especially if this only happens in the winter, before you do anything, you might want to take steps to find those openings that could use sealing. Do you have any friends who smoke? The could crawl aroudn the floor etc. puffing out their smoke and you could see if it rises faster in some places. If it's not too cold, they could crawl around the crawl space, where it might be more obvious. If not cigarette smoke, maybe there's a substitute??
If it happens in the spring too, you could turn the fan off and do the testing when it's warmer in the crawl space, if you're sure you'll get it done then.
First we need to know if the crawl space is also open to a partial basement , if there is plastic covering the ground in the crawl space, any insulatio n in the crawl space ceiling or plastic on the underside of the upper level floor joists. Also what is meant by "Dirty Air"? Is it visibly dirty or is it smelly, or what?? More information would make it possible to give more detailed suggestions!! !!!
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