Never seen this type of ductwork

I was doing a One Year Warranty Inspection today in Chandler, AZ and when I got up in the attic, I was like WTF. I have been doing One Year Warranty Inspections for 12+ years now and have never run across this type of ductwork. There must have been 30+ individual 3-3.5" non insulated ducts coming from this air handler, looked like an octopus! I did find one that was disconnected and of course reported on it. There were 4-5 small round registers in most the rooms.

I found two ducts (one at each end of the attic) that were terminated in the attic. This was an attic insulated with spray foam on the ceiling, my thinking is that this attic is meant to be conditioned since the ducts are not insulated.

I have done another One Year Warranty Inspection on this same street a couple months back and they had the ductwork I’m used to seeing, not this type.

I wanted to post to see if anyone has ever seen this type of ducting in residential homes and if so, can provide any type of insight…

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I think it’s a high velocity air system. I have seen a lot of older models, but yours looks more modern.


things keep changing, it is often hard to keep up …

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I have posted links about them for a couple of years now, and again just a few days ago.
Surprisingly, they seem to be mostly ignored.


It does look like high velocity. High velocity was originally intended for older homes that did not have room to run traditional duct work. The smaller duct work could be snaked in and around to the different rooms.

Maybe it was the HVAC Contractors solution to solving hot or cold spots in certain areas, High velocity systems are supposed to save energy. Here’s a good article I found on Google.

I have seen this type of system previously.
I have been a Design Build manager in commercial construction and worked with similar systems. The roof shingles of only two manufacturers were approved to be installed on the roof when I as involved. Probably more now, but the shingle does not have the air flow under the sheathing unless they utilize a panel flow system. Most shingles would not be covered by the manufacturer’s warranty for this application.
The individual supply air to the multiple locations is a great idea, but these types of systems and building envelopes are a different animal and require a lot of engineering/not just a builder wanting to try new ideas.
Innovation and technology moving forward. Stay up with it or get left in it’s dust wake!!

Thank you guys for the input. I’m going with High Velocity Air System. I’m trying to research if the vents that were terminated in the attic are suppose to be there to condition the attic space since the ducts are not insulated. I would think so. I have calls out to the builder and also Chas Roberts to try to get some clarification.

I’m not so sure about that, unless I am misunderstanding which exact ducts you are referring to.
It seemes to me that there are insulative sleeves over the pipes, such as extreme weather protective blankets, etc. Did you squeeze one to see if it ‘gave’ and contained a rigid pipe inside?
Remember, the air-flow is fast moving and wont sit around long enough to cool down in the piping.


i concur w JJ
unless ur absolutely certain there is nothing to report as far as ducts are concerned unless specific deficiencies were observed
identifying High Velocity Air System is best left to those qualified

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