What Can I Do About Sweaty AC Ducts? Why Air Conditioning Ducts Sweat or Leak Water 

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Also make sure when you take off your vent lid the area where the sheetrock corner meets the duct... check to see if its seeled up, I had sweaty lids causing a wet ring around the square opening. I solved this by taking the lid off and putting hvac 2inch wide foil all weather tape around the opening, spliting 1inch by 1inch on the edges. Yea, this ended up being a simple fingernail area where the attic was exposed and sucking hot air in the attic with the cold air coming out of vent. I Hope this info helps others.

Thank you so much for posting this video. I was horrified to walk down to my basement after a few days and see water and rust on my power tools. After watching this video I checked the nearby window and sure enough it was cracked open. Duh! But this video diagnosed my problem immediately. Thank you!

Little simple leaks make a big mess, good to know, Great video

Things don’t get sweat…it gets condensation! LOL 😂 “Sweaty AC ducts”…that’s a first to me…lol… Our home builders didn’t connect our air ducts the right way and one AC duct disconnected from the main pipe…flowing cold air within our basement ceiling and the wall to the furnace created so much condensation that it ruined a good part of our walls and my husband had to cut the ceiling to connect the AC duct to the main pipe. Great video! Duct condensation is a serious problem that can cause serious damages.

Great info thanks.

Thats last part about the warm/hot air in the attic just helped me figure out why when our a/c or heat runs why the air coming out is dank mildewy smell and I know there are several spots that don't have insulation on the ductwork..and an addition onto the house..it has the flex ducting and it had popped off the main air supply spiral ductwork and I just popped it back on not knowing about sweating etc can happen so when it starts cooling off here in Texas I will be up in the attic fixing all of this..Thank you for this valuable information..I have trying to figure this out for quite some time.

Very informative!

Thanks for this video. It's been 90+ in Philly for weeks now. And just last week it's been sweating. My guy jas a full bathroom in his man cave where the unit is. And he also votes through the house from th e back as well where the unit is. So I can see how warm tempt can do it. But we also ha e an issue woth it bei g overly hot upstairs but down stairs is always freezing. It's a wild ride

Amazing video tks

Great vid, I don't feel so overwhelmed now. I have 3 5 ton units in a converted commercial studio building, all units hanging horizontal above the hallway. All spiral ductwork sweats for the first few feet or more. Very humid environment probably very leaky old building. The units branch into studios but the hvac guys never installed return vents in the studios so I assume all air that runs through the handler is being sucked in from the outside. Sorry for the long post, does anyone think that when I cut reruns in the rooms back to the hallway, that might cut down on the humidity since it will be recycling drier air? Like the idea about the dehumidifier too

thank you dear

This video is priceless. The average person can follow the steps and avoid spending alot of money on repair or diagnosis. Thanks and thumbs up

Thanks

I had sweating ducts in a room that was unfinished so I wrapped them in insulation and haven't seen any issue as of yet ( since June so far and we are now in August here in Virginia). I have a bathroom on the same level where the ducts were sweating that doesn't have the fan cover on it yet. Do you think I could just put a cover on that fan to cover up the hole and it will stop this way or do I need to take down to drywall and insulate the ductwork in that small bathroom?

Can you recommend a pro dehumidifier &is it something I could install? I'm in rural America with. no help. Thanks

This help me a lot thank you and God bless you

How about sweating from duct in the garage? The garage is mostly warmer in summer cos it has only one AC vent opening into it?

I wish your company was in the NYC/NJ area. I have sweating ducts and it's difficult to get someone to even come out to look let alone diagnose it properly.

I have a strange situation where as all my ducts and registers are fine except one duct to the kitchen-dining room is sweating quite a bit, it is insulated. The water was trapped between the coil ducting and the insulation. Any reason why one duct is sweating ?

"You got a warn moist space down there... you can dry it out with the right appliance" lmao

OMG, I got "sweaty ducts" and didn't realize it until it started rotting my hallway ceiling. I tried to rewrap and tape them up but it's still dripping so I can't replace my ceiling until I get this shitt fixed. 😖

Hi, I found moisture "in" my ductwork dripping out of one of the plugs the furnace cleaners drilled and plugged. about 3 cupfulls. The outside of the duct is dry. I have the AC on for a couple of hours in the evening the last few days. Any suggestions?....Thank-you.

What's a good humidity level

Darn quacker…..😂😂 thanks for helpful advice

If anyone here can help, just had 15 seer heat pump/air handler installed one month ago. In hot garage in Florida, my 36 yr old air handler always had normal condensation on outside panels, this new one also does in some places. But the front panel right above the filter slot, has the insulation getting saturated on the inside, then the water is running down on the filter. Filter not getting crazy wet because it gets dried when the system runs. Had the AC guys back yesterday 95 outside temp, 80% humid, pretty much normal late summer day, and the guy said this is normal. He said it will not cause issues. Will dry over time. I worry that next hot season, the insulation will stay wet all the time causing mold, maybe black mold. I understand how condensation works and why. Inside the air handler is very cold, and the outside panel gets cold too, then the moisture in the air condenses when it hits the panel, but why inside?........Unit is one of the top tier companies and than this, it works great.....nice, quiet and cool.....

Same way you insulate pipes (cold if there in a space that can get warm

The sweaty air-duct is initially indicated the beginning of leaking through the ceiling dry-wall. The lower temperature setting, the more sweating you could get. Next week, I planned to learn how to replace the air-duct work because the labor is too expensive. How much would it cost, the labor for eight supplied lines?

How about the duct collars in the attic creating dew proint?

The bottom line is you have to keep cold air away from hot humid (eg, The heat exchanger ducts pulling cold air from outside the house into the unit in the winter) and hot air away from cold (eg hot air in an attic or crawl space that is in contact with a duct that carries cold air conditioned air). Well fitting, sealed joints (at the fittings and where it exits the house) will decrease mixing of hot and cold air in the duct and on the surface of the duct. The use of insulated ducts is a must for duct runs that carry cold air through warm areas and vice versa. Another scenario unique to Air Conditioning, is the speed in which the air flows through your (furnace) ducts. When you buy a furnace sized for your house the fan speed is set at XXX Cubic Feet Per minute but they don't know what size Air Conditioner you may buy and match to it, so they allow fan speeds to be adjustable. If you requested and A/C unit based on maxing out the Tons you've falling victim to the bigger the better flaw. See this article for how to match A/C to furnace BTU and the importance of adjusting fan speed right away after the A/C install. www.priorityenergy.com/article/control-humidity-optimizing-fan-speed ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-aJYC3Z3xFJM.html 40kBTU furnaces typically get 2 ton fans (800-900 CFM) 60kBTU furnaces typically get 3 ton fans (1,200-1300 CFM) 80kBTU furnaces typically get 4 ton fans (1,600-1700 CFM) 100kBTU furnaces typically get 4 or 5 ton fans (2,000+ CFM)

Insulate duct can solve this issue also and en hence efficiency ...

That is why I did not like to live in a "two story" home because you are almost impossible to track down where the water leaking comes from.

should you leave your foundation vents closed in AC season with a basement installed unit?

I just had 2 new units installed and 6 days later I was at the paint store buying paint to fix water damage in my kitchen ceiling. It did it again this year and cutting into the drywall and making a huge hole showed my air junction just sweating and dripping like crazy but for 15 years when we had the old units this never happened. So I wrapped the junction and then the vents began sweating and dripping. I have lots of drywall damage and it only started when the new units were put in. Long story turns out the unit that controls the downstairs, the fan speed in the evaporator coil was nearly double what it should be! It was never set at install. Like I said, it did this last year and 6 days later I've got repair issues where the junction box is. It did it again this year almost to the day of last year. I have had my install guys out here like 6 times and of course its not their equipment or their fault but he did say if I turn my downstairs to 73 or 74 ( we kept it at 70 with older units ) our problem will stop. And it did. Our upstairs unit we keep at 70 sometimes even lower and yet it doesn't do this. Any idea here on what is happening? No way is it coincidence that this started as soon as the new unit was installed. And why did moving my temp to 73 stop the sweating? Help me quack this case please! 😂 its a 2.0 ton American standard downstairs and a 2.5 American standard upstairs, which by the way the fan speed on it was never set at install either. It took over a year and all this damage to figure that out on both units. Thanks so much and good video! Oh. I'm in SC/NC border area if that helps. Thanks.

Do the crawlspace vent should be close or open?? My ductwork sweats a lot

How about now in the winter months when my central is off and I have water dripping through my ceiling vent? My duct work is in the attic. I've closed the vent and opened it and it still drips. Any suggestions on how to stop this or prevent it?

My furnace filter keeps getting moist and is deforming causing ac to not blow hard.

How do you clean rust and stains on duct from water?

What's a great dehumidifier for a large basement that won't break the bank?

dehumidifier

Cost off a bill plus I cantnot alloud in the loft

Thanks informative, jeddah. .......

Wait a second, if warm air 🤔 meets cold air, a heat exchange process takes place?

My house the ductwork is under the house in the crawlspace so it is outside in the summer heat, How do u stop duct sweat then?

Uninsulated wall stacks in an unconditioned space.

Old houses run a wall stack next to a chimney chase non insulated.

My floor ducts have sweat and now have rust on the surface. My basement is finished and my home is only 10 years old. No sign of any water water leaks. Am I doomed and need my HVAC replaced?

My ductwork is leaking in the basement in the center of the house help

Attic until with gable vents...

It’s 110 today. The heat evaporates the sweat before it starts.

From what I’ve read and leaking air conditioner like in an apartment is normal when it’s super hot outside especially because basically what’s happening is it’s condensation which is pretty much what you’re explaining

Can this happen from having the air on with windows open?

I got sweaty ducts

CAUTION: I fell from the roof yesterday night while doing this. For those who grew up in American houses will know not to step anywhere other than frames but it is not intuitive to those who grew up in concrete houses. I feel the video creators should add a caution in the beginning for people like me.

Would a dehumidifier help?

Ducks don't sweat.😊