Images Credit Sustainable TO
The Passivhaus (now called Passive House in North America) standard is usually thought of as a response to temperate or cold conditions, given its German origin. Certainly its annual heating energy limits are not going to mean a lot in New Orleans, where ArchDaily and Design by Many ran a competition to design a Passive House. But there is still a overall energy limitation which is tough to meet if you are going to provide air conditioning. The surprising winner was a Canadian architectural firm, Sustainable TO.
a well balanced concept of sustainability including minimal impact on the local environment, affordable to heat and cool, and affordable to build and purchase....Homes should be shotgun typology and strive to create cohesive neighborhoods.
In shotgun plans, the rooms are arranged enfilade without a corridor, which allowed for windows on both sides of a single room and good cross-ventilation. It is a French concept, seen from Versailles to apartments in Montreal to New Orleans. It doesn't work very well with our current expectations of privacy, so the architects have modified it:
The house reinterprets a traditional shotgun-style plan by mirroring two bedroom and bathroom units on either side of the main living space. The open living plan optimizes natural air flow and daylighting. The corridor opens southward to a flexible cantilevered side gallery that wraps around the house, providing shaded outdoor living space.
click image to enlarge
The architects write:
Organized linearly along a circulation corridor, the long axis of the house runs East/West. This organization addresses strategies of natural ventilation, daylighting, shading and solar heat gain. The south facade's deep roof overhang provides passive solar protection for the building's interior in the summer, while allowing passive solar heat gain in the winter.
Sliding panels on the south facade offer flexibility and protection from the sun, rain and wind when required. Windows on the north facade provide abundant daylight and natural ventilation while limiting solar heat gain.
The house gets the passive features right, with deep overhangs and louvres to the south and reflective metal cladding to stop the solar heat gain before it gets in, but it is still really hot and muggy in New Orleans, so it's got the required sh!tload of insulation to reduce heat gain and a simple form to reduce opportunities for air infiltration.
The active components are two mini-split heat pumps and two energy recovery ventilators, which differ from the usual heat recovery ventilators that we talk about in Treehugger; ERVs are enthalpic devices that transfer both sensible and latent heat, temperature and moisture. There is also radiant underfloor heating, which seems to be a bit of overkill in New Orleans.
This was an ideas competition; the prize is not a contract but a big HP printer. But architect Paul Dowsett is excited nonetheless:
"Winning this award is hugely exciting," said Dowsett, "confirming that it is possible to design an affordable and sustainable house that is also attractive -- no matter the climate -- and validates our approach to design and construction."
I learn also that Paul was the architect of Glen Hunter and Joanne Sokolowski's straw bale house, shown in one of my first TreeHugger posts: Sun, Wind and Straw: A recipe for Success
More on Passive Houses and Passivhaus:
Forget Energy Star and LEED, Green Building is Passivhaus
A PassivHaus Renovation: Heritage Meets Energy Efficiency
Bamboo Screens Shade Stunning French Passivhaus
The Passivhaus Had North American Ancestry
A Picture Worth TEN Thousand Words: A Passivhaus in New York