Close vents in winter?

Old 12-09-00, 06:36 AM
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I have a crawl space under the front part of my house which opens to a full basement under the rear of the house. The front crawl space has vents that allows air to blow through. The only problem with this is there is no insulation under the floor in that section of the house (built in 1922) and this cold air can come through the open section into the finished part of the main basement.

I am going to close in the area that is open from one part to the other but I wonder should I close the vents also, or will this cause more problems than it solves?

Thanks for the help.
Old 12-09-00, 03:22 PM
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I would not suggest you close off those air vents. They are there for good reason. You would be creating a huge problem doing so.

The under house area needs ventilation so moisture won't accumulate and cause mold, mildew and wood rot. The temperature changes between day and night alone, any time fo year, is enough to cause moisture to accumulate.

Good Luck,
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Old 12-09-00, 11:38 PM
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Now its a tie. I suggest close the vents in the winter & open them during the warmer more humid months. If your area temps are frigid the lower humidity levels of winter will not be as much of a concern as heat & energy loss. You did not mention if the full basement area is heated. If so, this warm air will migrate into the crawl to keep the floor warmer. You might consider insulating the walls of the basement to save further energy.
Old 12-22-00, 01:02 PM
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Thanks on both replies. I decided to close the vents and partition off the crawl space from the full basement. The rugs now stay on the floor on a windy day. I am periodically checking for condensation under the crawlspace but my drainage is good around that part of the house and every time I have been under there I almost choke to death on the dust.
My only other question now is should I insulate under that crawlspace floor or not? I doubt it would be cost effective (may take another 80 years to pay for itself) but would it make the floors feel warmer? They are 1" tongue & groove with area carpets covering about 80% of the floor.
Thanks again.

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