"Green" houses: US vs. Rio

US style:

Mike Strizki, a civil engineer living in New Jersey has converted his home into a completely energy self-sufficient abode that runs exclusively on a combination of solar and hydrogen power. Using solar panels, a hydrogen fuel cell, storage tanks, an electrolyzer to split water into Hydrogen and Oxygen, plus a custom made fuel-cell car, Mike benefits from a utility bill of zero dollars, and the comforting feeling that his activities don't produce any pollution. Currently the solution isn't in any way practical for mass adoption -- the initial cost was $500,000, with half paid by New Jersey state grants -- but Mike thinks that he could reduce this cost tenfold with more research and mass market production lines. There is also some concern amongst experts like Joseph Romm, a former Department of Energy official who thinks that the current relatively inefficient technology and the high cost means that this isn't a viable system for mass adoption just yet. Despite this criticism, Mike says "we have to start somewhere," even if early adopters (in this case rich Hollywood types with a conscience) are required to pay out up to $250,000 dollars to get in on the clean energy action. [source]

Rio style:

RIO DE JANEIRO (Reuters) - A floating house built out of trash in a reeking channel of a Rio de Janiero slum will be preserved as a model for recycling in a government anti-pollution campaign.

Luiz Bispo says his house [is] kept afloat by hundreds of empty plastic bottles...

Bispo, who earns a living by doing occasional repair and construction work, said he spent about $170 to build the house, mainly on cement and roof material. The rest came from construction waste and furniture he found at dump sites. [source]