oval duct insulation

[otto8]

If we are installing oval duct pipes though our walls, should they be insulated? If not why not and IF yes Why should we insulate them?

[NCHeat]

interior or exterior walls? interior no. If the ducts go thru an unconditioned space such as an attic or unheated crawlspace (or exterior wall, but I would advise against if possible) you will need to insulate.

[George2]

Do you realize that you get less airflow out of pipe that is ovaled?

[Gross]

interior or exterior walls? interior no. If the ducts go thru an unconditioned space such as an attic or unheated crawlspace (or exterior wall, but I would advise against if possible) you will need to insulate.

i disagree with that... for one, condensation may be a problem...but for 2 youll be putting BTUs where you dont want them instead of where they should go...sure they'll be with in the envelope of the building but not necessarily in the parts of the building that they belong.



also, oval pipe has a higher static loss BUT if its sized properly there will be no issue!


answer? yes, you should ALWAYS insulate your duct. when you control your btus, you control your comfort...and isnt that what heaters and a/c's are all about?

[genduct]

As NC suggests, wall stack in an exterior wall is not allowed.
Bare duct, rectangular or oval in an interior partitiion is the standard, because no one designs space for insulated duct. This is not as much of a problem if you turn your AC on in April/ May/ ? and don't turn it off until September/ end of season.
The difficulty comes if you only use the AC when it gets hot. Every time you "start-up" there is going to be the possibility / probability of Sweat" that means liquid water next to drywall or wood that is mold food.

So, how you operate your system will determine if you have potential problems

[otto8]

interior walls of our house. Some ducts will be inside the wall between 2X4's.. There is already exsiting ducts there that were used, they were not insulated.

[skibme]

You can insulate them,but you have to fir the wall out to do it. Oval pipe is designed to fit within a 2x4 wall. Sealing the duct is more important.