Here is an interesting link to a pan-European project to adapt Passivhaus standards to warmer climates in Europe with some consideration of the housing typologies used in the differnet countries.  It is interesting although it is a bit dry to read.

http://www.passive-on.org/en/

The downloadable information includes demo software to play with.

Bruce

> The total primary energy demand, including household electricity, is limited to 120 kWh/(m²a).

Where is a typical new US house at now?

Bruce, that is interesting. I always wondered exactly how to translate Passivhaus principles to a warmer climate with a cooling load rather than heating needs.

Bruce, this is a very hot topic in the US passivehouse organization, they have just completed the first PH in Louisiana ( http://www.greenbuildingadvisor.com...ayou-state ), and there are several on the way in Virginia right now (we're working on one...). It seems to be very new territory for the europeans, they have had the luxury of low-energy building without having to worry about high humidity.

The Louisiana house used an UltimateAir ERV with a PEX ground loop tempering the ventilation air, and an in-line ducted mini-split (1/2 or 1 ton Samsung?) with a bypass in the ventilation system, they claim it's working very well so far, seems to sit at 77 degrees with 50% humidity which the clients claim is a comfortable temp in summer. 4,000 BTU / hr peak load in the steamiest climate out there!

Some of the interesting strategies they are working with include using some underslab foam insulation, but only a few inches, so there is some cooling effect from the earth, but still insulation in wintertime from the ground.

More here on this project from the 2009 Conference: http://sites.google.com/site/phconf...udies-east

Thanks for posting those links. There are also some other interesting articles at the PHConference website.

Cooling is certainly a big Passivhaus issue in the humid south. If you read through the Passive On information, their "Passivhaus Design" for Seville did not meet Passivhaus energy requirements (due to cooling) while the Palermo house design met energy requirements, but not summer comfort requirements.

The groundloops seem to be a much better solution than air tubes for the south.

Bruce

Saft wanted to push the project's limits in an economical way to find out whether a Passive House project in the South could be financially sustainable, and all evidence suggests he's achieved just that.

"I wanted to find out whether these efforts are just for people who have lots of money, or if they can start to infiltrate the larger housing stock," Saft says. Judging by the results of Saft's project, it is possible. For less than $110 per square foot—financed through a conventional bank mortgage—and using only readily available construction materials, he built a three-bedroom, two-bathroom house providing a total 1,200 square feet of living space.

The house's 24-inch on-center advanced framing system uses a combination of 2x6 studs on the bottom half and 2x8 studs throughout the double-height space. In designing the wall assembly and cladding system, Saft and Klingenberg carefully considered the local climate. In addition to R-55 open-cell spray foam insulation between the studs, the house is wrapped with 1-inch-thick, foil-faced polyisocyanurate board to eliminate thermal breaks. A back-vented fiber-cement rainscreen cladding protects the house against moisture infiltration and acts as a built-in shading device by venting much of the heat accumulation, Saft says. A radiant barrier behind the rainscreen helps reflect any residual heat.

full article http://www.residentialarchitect.com/passive-design/architecture-professor-designs-first-passive-house-in-the-south.aspx

Good info but He says less than $110/sq ft. Cept he is a LEED AP and assoc prof of architecture. Wonder if he has all the costs in for a normal person? That is a pet peeve of mine in general when reading about projects in various magazines/trade publications. Many of them are architect owned/built and don't reveal any cost and when they do reveal, you don't know what really is/isn't included. Yeah, they accomplish some awesome things but at what price? It's hard to find good information for the average guy trying to accomplish a little bit more for the money. Dwell magazine started out more as modern homes for normal people but then morphed into a higher style money no object magazine.

The sense I get is the folks working on these issues in the US PH community are really advancing the field. Some of the people I know specifically working on this are John Semmelhack and Adam Cohen in Virginia, and the folks in LA I linked to. There are others, I'm sure, the conference is coming up in November in Portland OR. I would expect the southerners to be gathering and comparing notes.

The only climate that seems to really stump the PH techniques is the very hot desert SW. When we ran test models in Phoenix and Las Vegas they either blew the cooling energy limit or overheated badly, it was the hardest climate. In the cold climates you just keep on piling on the insulation in the model and you can always theoretically make it work, but that doesn't work with hot places because of the internal loads...

Perhaps evaporative coolers should be used in the hot dry areas.