AC flex duct "sweating"

Old 07-14-05, 07:55 AM
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AC flex duct "sweating"

I have an old house in southern Louisiana (very humid). The AC ducts all run under the house. I recently replaced the old ducts with new insulated flex duct. They get very wet on the outside of them. Should I be concerned with this?
Old 07-15-05, 06:49 PM
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Sweating ducts

This is an indication of insufficient insulation. Most of the flex sold around here in home improvement stores is only R-4.3, even when code says it must be at least R-6. Check the marking on your duct. You could add insulation but it would be a whole group easier to replace it with duct having a higher insulation value. If you can find R-8 or higher that would be even better.
Old 07-08-12, 01:37 PM
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I'll probably just wrap the duct considering it is only a 15 foot run. I don't understand why the other ducts are doing the same. Perhaps because this particular one is so close to the air handler and the air is especially cold? This has never happened before so I would think it has something to do with the 100+ degree temps as well, or the long run time.
Old 07-08-12, 01:58 PM
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You have to much humidity in the crawl. Make sure you have a sealed vapor barrier run up the walls close vents and maybe use a dehumidifier to lower RH rest of the way

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