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HVAC Exterior Duct Shrou

HVAC Package Unit Shroud Issues


Richard Acree

Those large metal boxes on the outside of a home, like the one in the picture below, are called Package Units. They get the name from the fact that they supply heat and air conditioning to all or some of the house, versus a split unit. A split unit is a HVAC unit that is composed of two parts, an interior furnace and evaporator unit and an exterior compressor unit. A package unit has all those components in the one large unit at the exterior.

At HABITEC Home and Building Inspections, LLC, offering Home and Commercial Building Inspections in Nashville and Middle Tennessee, we often see issues with these package units during our Home Inspections. This unit pictured below is an older unit and, like a lot of older components in a house, has some issues. This article will focus on one component of the unit, the large metal shroud to the right.

The purpose of this metal shroud is to provide protection from the elements and whatever for the ductwork that runs from the package unit inside the house.

When that ductwork is installed the openings it passes through in the foundation or house wall is rather ragged, leaving gaps that could be a point of entry for rain, insects and other critters. The shroud provides cover and also an opportunity to prevent entry of unwanted things like I mentioned above. The picture below shows a newer unit shroud and how it should look when the installation is complete.

Note how clean and neat the installation is against the brick. No water or insects entering here. Now let's go back to the older unit and get a closeup of the shroud-to-brick installation. See the photo below.

Look how the shroud is actually bent as if it has been impacted by something that maybe fell on it. Regardless of the cause, the situation now is wrong for two reasons. The shroud has been pulled away from the brick at the top and has been bent down so that it holds water and debris now. The openings at the top and sides can allow water, insects and other critters inside the house. And the depression that is holding water and debris becomes a breeding ground for mold. What we call mold soup. This is all wrong and must be flagged in a Home Inspection. Closeups of the situation follow below.

In the photo above if that mold soup gets high enough and flows over into that bend in the shroud, the mold soup can then drip down onto the ductwork that is below the shroud and guess what happens next. Then you have an opportunity to introduce mold to the HVAC ductwork system, which becomes the distribution mechanism to spread mold spores throughout the building. YIKES!!

In the photo below you can see a closeup of the old caulking that was originally installed at the shroud-to-house connection. Not doing much good now.

If the gaps at the sides and bottom of the shroud get large enough, and it doesn't take much, this opening becomes a highway for insects and critters.

Guess what critter is first to enter here and set up a household inside somewhere. Mice. Guess what critter is second. SNAKES! Look at the picture below. That is a snake skin just inside the basement and the metal in the background is part of the HVAC entry system.

So now you know why we grade these shrouds so harshly when we see them with these issues.

Thank you,

Richard Acree

Comments in this article are the copyrighted intellectual property of Richard Acree, President, HABITEC Home and Building Inspections, LLC, and are intended to educate and otherwise assist home owners, sellers and buyers, building owners, sellers and buyers, realtors, real estate investors, property managers, and lenders in the process of owning, buying or selling homes or commercial buildings. HABITEC is a residential (home) and commercial building inspection company serving Middle Tennessee including Nashville, Brentwood, Franklin, Murfreesboro, Smyrna, Mt. Juliet, Hendersonville, Dickson, Belle Meade, Columbia, Spring Hill and more! In addition to building inspections HABITEC offers Environmental Services for mold assessments, radon testing and water quality analysis. Additional information about HABITEC can be found on our website at, or call 615-376-2753.

Richard Acree is the author of the HABITEC Home and Building Inspections Blog and founder of the ActiveRain Group Tennessee Home and Building Inspectors. All are welcome to join and see more blogs like this one.

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