After a few thousands inspections, I just inspected my first house with "Jumper ducts". Anyone seen these before?

There were HVAC registers in the ceiling on either side of the bedroom door, apparently this allows for better airflow. They were not attached to the HVAC system and had no fan inline with the ducting. I know how a forced air system works and that it can pressurize the bedrooms if there isn’t enough of a gap under the doors. Just strange that I have never seen this before in 8+ years of inspecting.

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It’s the cheaper option to meet current standards, the better choice is a return that actually connects to the plenum, not just a room-to-hallway jumper.

Yes I see them frequently and recommend them when a bedroom has no return or jump duct and appear to have issues with flow.

Just as an aside I also see attempts at placing registers above doors on either side for the same purpose. They will work but they do typically reduce privacy for bedrooms.


Have you never been inside a Manufactured/Mobile Home?
Damned near everyone has them.
Also, I see them on homes that have been remodeled/rehabbed/converted/added on to.

It’s very typical here to have one or two returns with communication ducts connecting smaller living spaces. Beats the gap under the door.

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Ive seen the ones where you can hear/see into the other room for sure but never the ones I saw today.

Ive seen the ones where you can hear/see into the other room for sure but never the ones I saw toda

And that may be the reason for what you saw today… privacy.


And to think for years and years they called them “transoms.” Balancing air flow in offices across America. Now through the marvels of modern science the technology of “jump ducts.” Oh, the wonders of repackaging! SOS in a new wrapper.


Pretty common in newer builds in my area with the “McMansions” that have massive master bedroom suites. I’ve also noticed when they aren’t in place that the door SLAMS closed when the system is on. I’ve definitely written that up a few times and recommended something to balance out the airflow.

The manufactured homes I see usually just have unsightly grills over the doors. My 5th wheel just has HUGE gaps under and above the doors. Not much for privacy.

It’s becoming standard practice…In the old days they just cut the doors about an inch short to allow air to return to the register but they decided that wasn’t good enough any more…

I see registers over door ways and between adjoining bedrooms quite often in new builds, more often than not they are returns.

@dtearle did you have pictures you can share with everyone?

Every mobile/manufactured in my area comes from Oregon for some reason and I’d say 80% do NOT have the grill over the door style of jumper ducts accept for the laundry room

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Yup. I lived in Vancouver, WA for 20 years, and most all back there had the 2 inch cut off the bottom of the bedroom doors. My Ex lived in one, and she had cats. They used to always reached their paws under them like they were searching for mice or something!

That’s funny Oregon ships homes up there as I know there are a lot of manufacturers in the Seattle area. Last time I drove up to Seattle I was blown away at how many RV and manufactured home dealers/lots there are in the Tacoma area. When I’m trying to get to my inspection and am stuck behind three segments of a triple-wide on I-5 I didn’t realize they were going all the way to Seattle… LOL.

I don’t think I’ve ever seen a data plate in 8+ years that didn’t say Oregon. Granted I don’t inspect that many manufactured homes.

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It’s the cheaper option, unless you count lifetime energy costs. It takes conditioned air in to a maybe R6 duct in the unconditioned attic.


They are therre so you can shut the bedroom door. That is it.

The supply air entering the room can not leave the room with the same volume with the door closed. So, the supply air volume entering the room is reduced to the amount of air leaving thorough the crack under the door and to the outdoors through leaking windows.

You will never see new construction with a return in every room selling less than $1M. Contractors will not spend 2x the cost of the HVAC bill if they don’t have to.

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I’ll often see returns in each room on some larger 50s/60s era places. The labor and materials that goes into putting that all together is incredible. Especially in contrast to today’s construction. All that cutting and assembling is amazing. Same kind of thing with the EMT systems with electrical systems from roughly the same era. The thought of a builder taking the time to do something like that today is pretty funny.