I will explain what I would "Ideally" want. I would like the HVAC in the basement ceiling to Not require a soffit. Plumbing seems possible because the holes for the most part will be small enough to not affect the structural integrity. So the question is what is possible?

There is also a similar post here. They talk about the limits on what can be done to floor joists. From my understanding, it would not be possible to install any ducts through the floor joists. If I am wrong, please let me know.

Last would be what is the alternative? Is it possible to run the ducts through the roof attic? (I assume that opens a whole different set of issues) Plus that doesn't fix the cold air return which should be on the bottom if I am not mistaken. I would really like to avoid soffits if possible but everything I am researching is pointing that direction.

EDIT: The house is an existing home. The basement floor to ceiling is already at the 8' mark. The joists are typical dimensional lumber (not engineered)

Radiant/Hydronic Heating - The idea is awesome. If I was doing a new construction, this would probably be one of the best options.

"low-volume, high-velocity" ducted system - First time I have seen something like this. Its very interesting. I did read there are some disadvantages like noise and it can be costly to add.

To Clarify a bit more, I would like to keep the costs low so redoing the entire heating/cooling system is probably not going to be an option. (of course it depends on what costs would be). I intended to keep with the conventional heating/cooling and was more or less looking for a way to still it but avoid soffits. The image below is an example of what I had original wanted but it doesn't seem like that is up to standard?

EDIT-Image below is a not my current hvac. Its also a BAD way to do it. Was using it as a reference. enter image description here

  • 1
    Is this an existing home or new construction? You would like to avoid soffits, but is there room for a dropped ceiling? Commented Feb 26, 2015 at 20:00
  • I updated my question.
    – Kalel Wade
    Commented Feb 26, 2015 at 20:28
  • 3
    That is WAY too much hole in the TJIs. IIRC, my 20" tall units allowed me to put a 5" hole in the middle of them. Hope the HVAC contractor has insurance to cover the collapse of the house...
    – Ecnerwal
    Commented Feb 26, 2015 at 20:38
  • @Ecnerwal Ya, figured as much. You get images like these when searching - gets my hopes up.
    – Kalel Wade
    Commented Feb 26, 2015 at 20:41
  • 2
    @KalelWade That looks good - the image helped me a lot, actually, to understand the whole issue; And the warning now seems just right! Commented Feb 27, 2015 at 16:12

2 Answers 2


You could put in a non-forced air heating system - ie, hydronic or radiant, using water in pipes to deliver heat. You could use mini-splits for A/C only or for heat and A/C. You only need space for ducts if you need ducts, and there are plenty of houses without ducts...

Edit: you may be able to work with a wide, shallow duct so you can have a broad, not too deep soffit for the cross-joist duct run. Just be sure to get the sizing sorted out correctly (ie, a 12x12 duct cannot be replaced by a 3x48 duct (same area), as there's a lot more friction in the 3x48, but the correction factors for duct shape are surely available so you could pick a size that will work. It will cost more, but it may resolve your issues with soffits if you don't have to duck under them.

  • Since its an existing home, this may not work the greatest. If I was doing a new home, the idea of radiant/hydronic would probably work very well.
    – Kalel Wade
    Commented Feb 26, 2015 at 20:30
  • OK. Existing houses normally have existing ductwork, so that was not particularly obvious until your revision.
    – Ecnerwal
    Commented Feb 26, 2015 at 20:35
  • Ya, sorry about that - added the clarification. Your information was still helpful though because it does bring up different options.
    – Kalel Wade
    Commented Feb 26, 2015 at 20:42

One option would be "low-volume, high-velocity" ducted system (manufacturers include SpacePak and Unico) that uses a series of small 2" diameter ducts to distribute air. Depending on the size of your joists, 2" holes may be acceptable. As @Ecnerwal mentioned, mini-splits can be a good option too.

enter image description here

  • I like the idea around the low volume high velocity systems. It seems like the closest thing without reworking the heating and cooling system all together.
    – Kalel Wade
    Commented Feb 26, 2015 at 20:29
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    @KalelWade I'd try to find someone you know who has a high-velocity system and listen to it in operation before getting one installed. That high velocity comes with higher noise levels. I put an HV system in my small house a few years ago and if I had to do it again I'd go with mini-splits, they're much quieter.
    – Dan C
    Commented Feb 26, 2015 at 22:15

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