Thread: HVAC System

Do you report when you see uninsulated ducts in areas with no heat.

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Are these type of ducts allowed anywhere in HVAC, regardless of heated or not heated area?

That looks like insulated flex duct! Not sure of your question!

It's flex duct but there is no insulation.

Originally Posted by Brent Crouse

Are these type of ducts allowed anywhere in HVAC, regardless of heated or not heated area?

Without being there to verify there was no insulation ... those look like "air connectors" and not "air ducts", and "air connectors" have a VERY LIMITED use and a VERY LIMITED length.

Jerry, there is no insulation. They are very thin. The runs seem pretty short, limited to the closet space.

For one thing, they are not supported properly, as to whether they are even allowed to be used there is another concern - would need to have more information, such as the UL number on them, the manufacturer, etc., as they may (or may not) even be allowed to be used in that installation.

If that closet is not within the thermal envelope, then the answer is not allowed, if that closet is withing the thermal envelope ... maybe ... is the best I can do right now - but you can write them up for not being properly installed, and from there have a properly licensed and competent mechanical contractor determine if those uninsulated air connectors are even allowed.

Well the thermal envelope is a tricky question. It is a utility closet within the garage and the walls may or may not be insulated. They likely are insulated because there is a bedroom and bathroom above the area. I will get more info off the duct when I return to grab a radon test. Thanks for the help. The installation looked like a bit of hack job to me, but what do I know

Looks like the homeowner wanted some extra returns in the house. Complete hack job.

Those look like dryer slinkies, not real HVAC flex duct. I don't think it is insulated. Lack of support and poor install are easy write-ups. I'd add verify proper CFM to rooms by HVAC contractor. Those look like maybe 4", which isn't going to sufficiently supply anything beyond a bathroom. Don't see a bypass on that HUM either.

Originally Posted by Markus Keller

Those look like dryer slinkies,

To me, they look like they are larger than 4", but nonetheless ...

... "dryer slinkies" are not even allowed to be used for dryers.

Well, JP you ought to clarify you are allowed to use flexible 'transition ducts' on dryer vents if using the prescribed materials under the prescribed conditions but............

Somebody tell me how you use a flexible transition duct and maintain a male-up pipe orientation? I've never seen a flex hose that was sized to slip inside a rigid pipe that didn't downsize the duct.

Originally Posted by Bob Harper

Well, JP you ought to clarify you are allowed to use flexible 'transition ducts' on dryer vents if using the prescribed materials under the prescribed conditions but............

Somebody tell me how you use a flexible transition duct and maintain a male-up pipe orientation? I've never seen a flex hose that was sized to slip inside a rigid pipe that didn't downsize the duct.

Those little blue pills might help with rigidity...

Are you sure those are heat ducts and not return air ducts?

A contractor evaluated it and said it was fine, just cheap. I asked him about the duct sized and lack of insulation and he could have cared less. Then the buyer was there and asked how much to improve it and he said 1000 to 1500. Glad I said something about it, I don't want to pay for it

Originally Posted by Bob Harper

Well, JP you ought to clarify you are allowed to use flexible 'transition ducts' on dryer vents if using the prescribed materials under the prescribed conditions but............

Bob,

Except those slinkies *are not* approved for use as transition duct (dryer connectors) - neither the foil types nor the plastic ones, ONLY the flexible metal ones.

What state is that in? In CA code is a minimum R-4.2. As far as that furnace being in the envelope, it doesn't appear to be. I'm not sure what contractor would say that was O.K. If you measured the external static pressure (ESP) I'm sure it would be far outside the capability of the blower. Just a drastic loss in capacity for the system, but hey, if the home owner wants to run a 5 ton A/C to get 4 tons of cooling, good for him.

If the installation is in an unheated space you better check the water piping and water softener too.

There is also a loss in thermal efficiency here. In New Jersey all branch ducts in new construction must be minimum of R-6