i am not an expert but this house doesn't look that green to me. A lot of square feet and what is with the big fat concrete basement?: "The steel frame and concrete basement generates an efficient interior volume which provide both space and functionality "??? (you mean you can walk around inside of the house?) It sounds like it is made up of a lot of worn over old ideas like having windows facing south makes it an efficient house. we need more forwrd thinking than this. It does have some geothermal, however, which is good.

I do consider myself something of an expert in green construction, and I have to say this is one of the greenest of homes I have seen mentioned at TreeHugger. This is a relatively small home. The layout pics would seem to suggest otherwise but a good chunk of the space in the floorplans is the atrium and balconies which are functional parts of the passive solar design, and while they are obviously part of the home they are not living spaces that need conditioning like the rest of the house. The concrete basement is neitheir big nor fat. It is a relatively small basement, and the poured concrete is rather thin when you take into consideration that most of the thickness of the wall is foam insulation. Furthermore, the concrete has a high concentration of slag, making it much more energy efficient. The shape of the house is inherently space and energy efficient. Stacking a home vertically reduces space needed. And vertical spacing also makes the home more energy efficient because less of the floors and ceilings are directly facing exterior, reducing heat losses. Since much heat is lost through the ceiling (because hot air concentrates in the ceiling), much basement heat filters up to the first floor, first floor heat to the second floor. I suspect that the steel frame was chosen to reduce amount of construction materials required. In any case the steel frame and basement combination clearly enables the efficient use of space, material and of energy efficient function. It is most definitely a passive solar designed house. Shape - long and thin and stacked vertically; orientation - facing south toward the heating sun; location within the property - buffered by trees to the north to block cold winter winds and open area to the south which does not block sun; interior layout - keeping secondary living areas (kitchen and bathrooms and storage) on north wall to buffer primary living areas from cold north wind heat loss and open floor design to allow for diffusion of natural daylight, of heated and cooled air, of breezes and of ventilation; relatively small size - to enable atrium to provide significant portion of winter heating and summer cooling needs; passive cooling through use of exteriour shading in the form of roof overhangs, balconies and exterior shade structures. Adequate window placements for solar heating, daylighting and channeling breezes and ventilation. Advanced thermal mass in the form of gypsum wallboards encapsulating significant quantities of advanced phase change materials. Also plenty of thermal mass in the concrete floor slab of main floor. Adequate levels of insulation. High performance windows. I could go on and on. They have done a good job of integrating all of the passive solar and cooling design principles for their latitude and climate. In my opinion, this is in itself an impressive achievement and the most important one. It is pretty pointless to incorporate advanced systems, such as geothermal heat pumps, if the house requires preposterous amounts of heating or cooling energy. First priority is to design the home to require minimal resources to function properly. And they seem to have done a decent job on this. But they didn't just stop at this. They then went ahead and incorporated a host of advanced systems. Earth tubes for pre-heating and cooling air (by the way, if anyone knows where I can get the schematics on their cool tube designs, I would be greatly appreciative). An advanced rainwater collection system. An advanced wastewater recycling system. A wind turbine. Advanced solar water and air heating system. Advance radiant floor heating system and controls. Ground source heat pump. And so on and on.

I have spent a good chunk of my life studying green architecture, and spent five years researching and designing my own green home and another four building it with my own hands. I consider my home very green and fairly advanced in terms of green architecture, but I have to say that this house is more advanced than mine and probably greener too.

I think Lloyd picked a winner with this one. And I don't say this lightly since more often than not I harshly criticize homes spotlighted here in Treehugger which I find inappropriately labelled as green. I'd say this applies to more than two thirds of home designs mentioned on TH. And I praise very few. This one definitely deserves praise as green. If there is one thing that bothers me it is that this is a demostration project home, and I am afraid no one would build such a home due to cost - but this is a guess since I am simply assuming most of these advanced systems are very expensive.