Comments on: Grading an Attempt to Get Ducts Inside Conditioned Space https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/ Building science knowledge, HVAC design, & fun Mon, 13 Dec 2021 17:54:35 +0000 hourly 1 https://wordpress.org/?v=6.6.2 By: Allison Bailes https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9600 Mon, 12 Sep 2016 20:55:28 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9600 Well, that sounds reasonable,
Well, that sounds reasonable, Sean. But yesterday I took a walk through the second house on the site, which just got framed last week. The I-joists are 14″ deep and made by Boise Cascade. According to BC’s own documents (https://p.widencdn.net/pclohu), the holes shown here are OK. Also, judging by what I saw, it seemed the holes were precut but I couldn’t find anything on the BC website about them offering precut I-joists.

]]> By: Kris https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9603 Mon, 12 Sep 2016 20:09:40 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9603 Thanks David,
Thanks David,

I guess the builder is trying to save a couple of hundred dollars by use the rectangular, out the back, stud cavity ducting.

]]> By: David Butler https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9602 Fri, 09 Sep 2016 21:21:34 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9602 @Kris, there’s nothing
@Kris, there’s nothing intrinsically bad about square (actually rectangular, typically 3.25 x 10) exhaust ducting. The hood will be down-rated a bit but if it’s sized correctly to begin with, all of that is taken into account. In my experience, most hoods move more air than necessary to get the job done.

BTW, mounting a range & hood on an interior wall doesn’t necessarily require routing the duct through stud cavities. It can be vented up through an upper cabinet. From there, the duct can turn horizontal if there’s conditioned space above.

]]> By: Kris https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9601 Fri, 09 Sep 2016 15:49:17 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9601 Question to Allison or anyone
Question to Allison or anyone else.

I’ve noticed in my area (Atlanta) new townhomes are equipped with dedicated range hoods instead of the obligatory POS recirculating/microwave bundle.

My question revolves around the exhaust ducting. Since I’m talking townhomes the stove is always placed against an interior wall. The ducting for the range hood is square and travels inside the stud bay instead of they typical round pipe heading straight out the top of the hood into the ceiling.

How good/bad of an idea is it to use this square in-stud duct design?

tia.

]]> By: Sean @ SLS https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9599 Thu, 08 Sep 2016 17:02:08 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9599 I give an F also for framing
I give an F also for framing & while it might have been “engineered” to allow for it (giving the benefit of the doubt), they should have only done 1 large hole for the duct per the guidelines — http://www.woodbywy.com/document/tj-9001 & then used a smaller hole to run the wires

As for single return versus one for every room – plusses & minuses for both as pointed out by David but especially when it comes to code testing. With that best is multiple though you can use a single if you design stuff properly

]]> By: Kris https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9598 Thu, 08 Sep 2016 16:06:14 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9598 +1
+1

]]> By: Bo Dramer https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9597 Thu, 08 Sep 2016 02:37:18 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9597 Another great article,
Another great article, Allison.

]]> By: David Butler https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9592 Thu, 08 Sep 2016 01:45:20 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9592 Robert wrote: “(central
Robert wrote: “(central returns) are probably the main reason air distribution systems don’t work as well as they should”

I strongly disagree. The main reason air distribution systems don’t work is because of poor duct design and installation practice. A central return is never evidence of poor design. The real problem (to your point) is under-sizing central returns and not providing low resistance return paths. In low load homes, door undercuts can often handle smaller rooms but jump ducts and/or transfer grilles are always an option.

The rationale for having a single return location isn’t just a matter of money. A single return offers superior performance to branch or radial return topology. A ductless return, where possible, is even better. Here’s why:

a) Yes, a single return costs less, which ain’t nothing!

b) A single return (especially ductless) causes a lot less interference when trying to route ducts through floor trusses and soffits. Let’s not make it even more difficult to move ducts inside conditioned space!

c) A single return materially reduces blower energy, all else being equal.

d) In a basement, a ductless return that serves the floor(s) above ensures good air mixing and keeps basement humidity under control when there’s little or no sensible load in the basement. Isolating a finished basement from the rest of the house is one of the dumbest things we can do.

]]> By: Allison Bailes https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9596 Thu, 08 Sep 2016 00:48:54 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9596 Bob, if indeed I were stating
Bob, if indeed I were stating that trunk and branch is superior to radial, you would be correct that I would have been incorrect. But I wasn’t stating that. Radial can work fine if designed and installed properly. There’s nothing that makes one inherently better than the other.

But then, in theory, theory and practice are the same. In practice, they aren’t. I’ve seen more bad radial systems than trunk and branch systems.

]]> By: Bob Ellenberg https://www.energyvanguard.com/blog/grading-an-attempt-to-get-ducts-inside-conditioned-space/#comment-9595 Thu, 08 Sep 2016 00:42:52 +0000 http://energyvanguard.flywheelsites.com/?blog_post=grading-an-attempt-to-get-ducts-inside-conditioned-space#comment-9595 You stated, “The duct system
You stated, “The duct system here is radial rather than trunk and branch”. That statement by itself I believe is incorrect if you are stating trunk and branch is superior to radial. If the air handler were in the center on the house and it was a true radial (like the spokes of a wheel) with straight smooth runs, it would be better than a trunk and branch. I agree that this system in this house should be a trunk and branch but a proper radial duct layout (seldom seen) I believe is superior.

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