# condensation from ac in crawl space



## Mike Swearingen (Mar 15, 2005)

Jack,
Your solution will help get rid of that condensation, but there is an additional solution to your problem.
I built our home in 1977 and had that same problem for a number of years...excessive dripping condensation on pipes and ductwork in the crawlspace under my home. Being on the waterfront of Albemarle Sound less than 50 miles from the Atlantic, we have very high ground and air moisture. Ground plastic does no good in such high air humidity.
Ventilation was the solution.
I ordered a 10" louvered exhaust fan (actually made for dairy barns) with a small 1/30 hp motor and installed it in a custom-made pressure-treated plywood and 2X4 door. I ordered the fan from www.wwgrainger.com .
The crawlspace door that I made was 5/8" pt plywood with a 14" square hole cut in it. The hole has a single layer of pt 2X4s around it on the outside and a double layer of 2X4' around on the inside to A. accomodate the weight and louvers of the fan and B. hold layers of hardware cloth and screen on the outside.
I plug this fan in under the house and open all of the vents and let it run 24/7 year-round except for freezing weather. 
That particular exhaust fan is about double the size of what the Tech Support man at W.W. Grainger recommended as the minimum size for the cubic footage of my crawlspace, as I believe that there is no such thing as "too much" ventilation. 
Before you start shopping for an exhaust fan, calculate the cubic footage of your crawlspace (length X width X height (ground to subfloor).
Good Luck!
Mike


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## Jack Hass (May 21, 2006)

Is the fan loud?
Can you hear the fan from inside your house?

you replaces your crawl space door with this fan set up right?


now the dumb question:

is the fan blowing air into the crawl, to be pushed out of the vents, or is it sucking air out of the crawl so there is constant air coming in through the vents?

do you think it matters which way you do it?

how long has your fan lasted running 24/7?

what do you think the life of the fan will be?

I assume 1/30 hp uses very little elect and you don't notice the difference on your electric bill?


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## oddjob (Sep 19, 2005)

Jack the insulation on your refrigerant lines might be the problem. Is the insulation breaking down ,needs to be replaced or maybe just over wrapped.


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## lbaccari (Jul 5, 2006)

Check out a product called Smart Vent. www.smartvent.net


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## yudamann (Jun 27, 2006)

This only addresses the symptom, not the disease. Increase the thickness of insulation on refrigerant vapor [cold] and domestic cold water pipes is the answer.


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## oddjob (Sep 19, 2005)

since the water was puddled on the plastic, apparently you have a vapor barrier already in place. So the moisture (humidity) isn't coming from the earth. More ventilation will only worsen your pipe sweating issue, allowing more outside humid air into your crawlspace(IMHO) Try reinsulating the refrigerant lines.


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