Laundry room register in NEW BUILD not connected

#1 Did a pre-purchase inspection of a New Build today. Need a bit of help here to understand why a ceiling register in a laundry room would have a flexible metal duct connected to it and sticking straight up in the attic about 4’ high and not connected to anything! Saw this before with a metal rigid duct 2’ tall in a 2003 home and not connected but now wondering what this could be other than an oversight by the HVAC installers (maybe the same installer???)? Never heard of anything like this and called it out on the last one but wondering if this is some sort of odd requirement? The laundry room does have a door going to the garage and another that leads to the hall, making it a separate contained room if that is some issue. Laundry room also has a separate dryer exhaust properly vented. Pics are attached for better understanding. Any assistance is appreciated.

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I’m confident that it’s wrong, but don’t know enough to say what’s wrong.

Is there and HVAC supply duct and register? (there should be, but if not perhaps this is an improper/incomplete attempt to include one).

Is there an exhaust fan ducted to the exterior? (there should be, but if not perhaps this is an improper/incomplete attempt to include one).

Is there a water heater in the room? (if so, it may be an improper attempt to provide combustion air)…

Great questions Chuck and thanks for the help. There is a register feeding the room that is properly ducted, there is no exhaust fan venting the room and there is no water heater in this room. I’m guessing the same company from my previous inspection is still in business with the same crew unless there’s some obscure code floating around out there!

Now… there is a gas supply line provided for a gas dryer but not connected.

Thanks again.

The gas supply line is your clue.
The gas dryer exhausts through the dryer vent, along with the hot, moist air and dryer lint, which is why they are so dangerous and require cleaning annually at a minimum.
What most inspectors don’t think about is the need for ‘combustion air’ and/or ‘make up air’ for said gas fueled dryers. They gotta get that air from somewhere, and in a “seperate contained room”, that would be your metal duct in question.

https://www.iccsafe.org/forum/intl-plumbing-mechl-fuel-gas-codes/dryer-combustion-air/

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JJ, thanks for the help. This makes perfect sense! Wish I could recommend if they use an electric dryer to seal that vent but not going there. If it were my house I’d be doing just that or add a louvered door to the laundry room!

A wide open inlet to outside or attic isn’t wise and a screen or hardware cloth would be a real good idea.
Back to the dryer. Electric or Gas - 100 up to 225 CFM of air leaves that room when the thing is on.
If its a tight room with minimal door under cut and no source of air from rest of the house or outside, it will affect dryer operation.
Like Chuck said, Include a gas fired water heater in the same room and there are real consequences.

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I’ve seen these for the first time this year and was wondering the same thing! Thanks for the information JJ.

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Remember, an electric dryer still needs to move air to expel the moisture from the clothes. Only difference is no exhausting of any ‘products of combustion’.

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