Condensation on cold/hot air plenum... why?

[acolic]

Perhaps someone can explain what is happening and what the solution is.

I happen to be running some wires for a speaker in my basement and I noticed that a 6“ warm/cold air plenum running along the back wall of my house had water dripping along it’s outside surfaces.

The AC is on right now so all areas of the house are cooled including the basement. Although the basement is cooler than the rest the house.

Is this condensation?

Is there a solution?

Thanks

Alex

 

[Sparky617]

Just like a glass of iced tea on a hot & humid day the humidity in your basement in condensing on the colder duct. I suspect your basement isn't getting the full benefit of AC to dehumidify the air. Is there a return vent in your basement? Without pulling the air from your basement through your HVAC system it won't get dehumidified by your AC unit. The basement will naturally be cooler than the rest of the house since it is up against colder earth. My unfinished basement doesn't have any supply lines today and is still a good 10 degrees cooler than the upstairs despite being fully above grade on the back of the house.

You may need to add a return air vent in your basement or add a dedicated dehumidifier to your basement. Insulating the ducts will help by keeping the more humid air from your basement from condensing on the duct work.