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Jack Hass 08-18-2007 09:48 PM

condensation from ac in crawl space
I went in the crawl space today and I had some standing water on the plastic in the crawl space under where the ac line runs from the outside heat pump to the inside unit.

All together I bet I had a gallon on water on the plastic.

I had flooding at one time and I want no water in the crawl space.

We have had 30 days of 100 plus weather this month.

What is the solution to stop the condensation?

I was thinking about hanging a half pipe under the ac line and let it catch the water and run it to the sump pump.

Mike Swearingen 08-18-2007 11:19 PM

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 .
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!

Jack Hass 08-19-2007 11:50 AM

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?

oddjob 08-22-2007 03:38 AM

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.

lbaccari 08-23-2007 09:24 AM

Check out a product called Smart Vent.

yudamann 08-23-2007 10:45 AM

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.

oddjob 08-23-2007 06:01 PM

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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