single family residence in southern calif

[hanque]

Hi All,

I'm an owner/ architect working on my own house in Los Angeles.
It's a multi level hillside house partially buried:

I'm planning 3 zones based on how I predict the house will be occupied.
I'm assuming that a split system is the way to go but I really don't like the fact that cool air & warm air come through the same registers.
Two solutions come to mind:
1. Install duplicate ducting to each conditioned room one high, one low (not really liking this idea).
2. Install radiant flooring for heat and ducting for cooling only (radiant flooring seems excessive and is rare in southern cal).

Any other ideas out there?

Thank you!!

 

[Shophound]

>>>>Shophound, I'm not sure I'm reading your critique correctly, but are you suggesting that ducts in general are problematic? >>>>

No. It is where people often choose to place ducts that create problems.

* Ducts in attics = HVAC capacity loss and possible building pressure concerns due to leakage.

* Using building structural cavities as air conduits = same leakage and capacity concerns.

* Inferior duct design = capacity loss and comfort problems

* Inferior duct selection = capacity loss and comfort problems

In short, duct design and execution is nothing to take lightly, in spite of how often that very thing is done. "Oh, just throw some flex duct here or chase a length of hard pipe there...you'll be fine!" Would be nice if it worked that way in reality, but I've been around too many botched duct designs and installations to know differently.

Good duct design is just as much good engineering as it is good installation of an engineered design. What I really was getting at in my prior posts is that if you're building a brand new house, concentrate on making that house gain or lose heat SLOWLY. That way we don't have to throw tremendous amounts of energy into the space to keep it comfortable. Meaning your duct design intensity and HVAC BTU requirement decreases. Energy consumption decreases. Comfort year round increases. As an architect designing his or her own house, these aspects should rate high on your "must have" list.