Reduce Ductwork


  #1  
Old 03-16-15, 07:41 AM
S
Member
Thread Starter
Join Date: Nov 2005
Location: Rochester
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Reduce Ductwork

Hello,

I am currently in the process of finishing my basement and I was looking to see if I could safely remove the last 12" of duct from a soffit which I will be framing. Normally I would extend the soffit down the full length of the ceiling but I will be having an egress window installed and as it currently stands my soffit would run right into the top portion of the window. I have included a picture for reference.
 
Attached Images  
  #2  
Old 03-16-15, 09:21 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,170
Received 2,272 Upvotes on 2,024 Posts
Ok, so what's your question? It sounds like you know what to do. If your asking about removing the end of the duct it should be no problem as long as there is nothing connected to it.
 
  #3  
Old 03-16-15, 10:44 AM
S
Member
Thread Starter
Join Date: Nov 2005
Location: Rochester
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
My only concern involved throwing off the balance of the system if I went ahead and reduced the duct. I have spoken with some HVAC workers who said they carefully engineer the ducting to be most efficient and I didn't want to mess this up. It sounds like this is a non-issue though.

Thanks
 
  #4  
Old 03-16-15, 02:17 PM
S
Member
Join Date: Feb 2014
Location: USA
Posts: 1,771
Received 0 Upvotes on 0 Posts
Yea I think it's a non issue too. Make sure there isn't a duct on the top feeding a room. Is that a supply or return duct?
 
  #5  
Old 03-16-15, 03:52 PM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,170
Received 2,272 Upvotes on 2,024 Posts
Often what HVAC installers do is fabricate trunk lines in their shop before coming out for the instal. They are often made longer than needed as it's just a trunk for tying lateral ducts into. If there is no duct coming off the end you circled (you still have not said) then it's a dead end and is not involved involved in the active airflow of a "carefully balanced" system.
 
  #6  
Old 03-16-15, 06:13 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
If it is a return & there's nothing connected to that section of duct, take it down & cap it off.

If it is a supply, it's a different story. I see a connection at the next bay. If you shorten that trunk, you will probably change the air flow out of the register in the next bay.
 
  #7  
Old 03-17-15, 06:25 AM
S
Member
Thread Starter
Join Date: Nov 2005
Location: Rochester
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Yes this is a supply line and the closest connection currently is about 20" from the end of the duct. If I cut the line it would now be approx 6" from the next connection.
 
  #8  
Old 03-18-15, 07:25 AM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
You can try cutting it back. It may change the air flow through the last register on that trunk, it may not. Do this before any other construction so you can tell if it will work or not. Just make sure it's done in such a manner to allow the duct to be put back together if needed.
 
  #9  
Old 03-19-15, 09:35 AM
S
Member
Thread Starter
Join Date: Nov 2005
Location: Rochester
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
That sounds like a good plan. I will be cutting the duct this weekend.
Thanks!
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: