Supply Duct Sweating - HVAC - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC


CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 07-31-2011, 04:35 PM   #1
Member
 
MikeKy55's Avatar
 
Join Date: Nov 2009
Location: Louisville KY
Posts: 323
Rewards Points: 254
Default

Supply duct sweating


I notice last night the supply duct to the kitchen (comes off the main trunk about 5 feet from the register) is sweating and drops of water are falling on the basement floor. This is in what I call the mechanical room which is about 10 by 10 and unfinished. The furnace, water heater, sump pit and ejector pit are in this room. This is the first time I have noticed it. I run a dehumidifier in the basement and humidity is around 50 to 60%.
Can I replace the metal ducting with insulated flex duct and fix this? My concern is the rest of the basement metal ducts which are above the finished drywall. I wouldn't want those sweating.

Advertisement

MikeKy55 is offline   Reply With Quote
Old 07-31-2011, 04:44 PM   #2
Member
 
Join Date: Dec 2006
Posts: 17,158
Rewards Points: 6,652
Default


Dewpoint is what is causing this. Happens when cold air meets warmer air. Look at that can of soda or beer, or glass of iced tea. Same concept.

Advertisement

gregzoll is offline   Reply With Quote
Old 07-31-2011, 05:09 PM   #3
Member
 
Join Date: Mar 2011
Location: Ohio
Posts: 1,646
Rewards Points: 1,000
Default


just buy some duct insulation for the metal duct. they make it in all the standard duct sizes. its like flex duct with the flex duct inside. they also make a wrap around. any good plumbing and heating supplier should have what you need.

http://www.reflectixinc.com/basepage...&pageIndex=544


http://www.homedepot.com/Building-Ma...atalogId=10053
DannyT is offline   Reply With Quote
Old 07-31-2011, 06:01 PM   #4
REP
Member
 
Join Date: Jul 2011
Posts: 615
Rewards Points: 500
Default


insulating the duct will help quite a bit.
You should also look for air leaks in the ductwork.
Insulate the house baseplate area
Since you already have a dehumidifier you might also need to increase fan speed.
I wonder if you have moisture seeping in through the basement floor and/or walls?
I'm also wondering if your ductwork system is too small which might be slowing the air movement causing the duct to get so cold that it causes condensation with only 50-60% RH.

Last edited by REP; 07-31-2011 at 06:05 PM.
REP is offline   Reply With Quote
Old 07-31-2011, 06:30 PM   #5
Member
 
MikeKy55's Avatar
 
Join Date: Nov 2009
Location: Louisville KY
Posts: 323
Rewards Points: 254
Default


The duct insulation makes sense, thanks. The basement stays dry. I have been finishing it and drywall dust and the like remain a powder. So much so I won't sweep it (it becomes airborne if I do). I vac it up each time there is some. Also I just tiled the bathroom down there and the grout dried pretty much over night.

Oh and the duct work joints are all taped.
MikeKy55 is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help with return air duct gasbie HVAC 4 06-20-2011 07:54 PM
How many round ducts can connect to an 8" x 12" supply duct? Charlie3872 HVAC 0 06-15-2011 09:49 PM
Metal duct or flex? smokey982 HVAC 6 08-06-2010 07:20 AM
Cold air in duct in furnace room? DIYguy2000 HVAC 6 12-23-2009 11:42 AM
Extending Water Supply Box In Laundry Room hsl Building & Construction 0 11-18-2009 10:21 AM




Top of Page | View New Posts

 

Search Engine Friendly URLs by vBSEO 3.6.1