Ask Experts Questions for FREE Help !
Ask
    sbauer7609's Avatar
    sbauer7609 Posts: 9, Reputation: 1
    New Member
     
    #1

    Jul 6, 2009, 11:20 AM
    Trunk lines
    My house is a C.P. Morgan home that has all flex ducts ran off the plenums, supply and return, with no trunk lines. Would it be better to run the trunk lines off the stacks or can I get adequate airflow without doing all that work and money. I already got all of my sizing off the Manual J and D. Any tips on doing them to save a little dough... especially the returns? Should I insulate the ducts... they are in the attic.
    siberianair's Avatar
    siberianair Posts: 360, Reputation: -4
    Full Member
     
    #2

    Jul 6, 2009, 12:21 PM

    If you by flexduct that is already insulated than no you don't need to reinsulate them. I would get a higher rated insulated duct to do the job since you are installing in an attic.
    sbauer7609's Avatar
    sbauer7609 Posts: 9, Reputation: 1
    New Member
     
    #3

    Jul 6, 2009, 01:28 PM
    I forgot to say that I was thinking about running all new trunk lines for supply and return along length of house. I don't know how much better this would help the air flow rather than long spans of flex.
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #4

    Jul 6, 2009, 02:21 PM
    All duct in a unconditioned attic space has to be insulated by code and the more insulation the better. There are different classes of flex duct and I suggest you buy the highest R value available. I have successfully installed systems using flex duct only but the instructions must be followed exactly of you will choke off part of the air supply.

    While I like the appearance and function of sheet metal duct there is a major cost difference between it and flex when done properly. In a attic space I would insulate both inside and outside of the duct and that gets very expensive. Items like duct wrap are available for the outside of the duct BUT it is a pain to install in a attic space.

    Below are some rules for flex duct install according to SMACNA which is the true duct standard of install in the USA.
    Attached Images
     
    Attached Images
  1. File Type: pdf We.pdf (69.0 KB, 216 views)

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Hole in trunk; to fix or not to fix? [ 1 Answers ]

I have a massive Catalpa (sp) tree in my front yard. The trunk is about 4 feet in diameter at ground level. About 10 feet up the trunk, there is an oblong hole that's about 10" tall by 4" wide. I think squirrels are living in there. While I don't want to harm the squirrels, I don't want to lose...

1994 Caddy Trunk Motor Won't Close Trunk [ 7 Answers ]

Hi Guys, I have a 94 Caddy that the trunk closure motor,(see images) won't operate when the lid's closed. I've checked the 15 amp fuse and it's intact and not blown, Is there anything I've missed. Is there a override so I can close the trunk. I have a week before rain's forecast in my area but...

Spilled gas in trunk [ 1 Answers ]

I spilled gasoline in the trunk of my car. Wanted to know if there is anyway to get rid of smell? The smell is pretty overpowering. I have been letting the car air out everyday since its happened but it still smells.

Trunk won't stay up. [ 1 Answers ]

I have a '93 Honda Accord. The trunk won't stay up with out using a support. It looks like it has two torsion bars but I am not sure how to replace or even if they are the issue. Help?

Electrical equipment with coax lines connected backfeeding 40-60 volts through lines? [ 4 Answers ]

Hi I have a question for any electricians. I am a cable technician and do installations for Cable,Internet,& Voice in homes. What I have encountered a lot is electrical back-feed coming through the copper coax lines feeding from vcr's and tv's in the house which are plugged into electrical outlets....


View more questions Search