What goes around comes around.

That’s the idea behind so-called sustainable architecture, or “green” buildings, as they are commonly known, but only part of that theory has to do with recycling. According to industry members involved with such pet projects, one of the most important benefits of being environmentally friendly is an immediate improvement in life quality.

“It’s really a high standard, even if you go beyond the green issues,” the principal of the architectural firm Pelli Clarke Pelli, Rafael Pelli, said.

His firm designed the city’s first green residential building, the Solaire, which completed construction in 2000. Their current projects include the Verdesian.

“There are no requirements for supplying fresh air to [residential] buildings,” Mr. Pelli said of New York City’s housing codes.

There are regulations about removing the air, but “typically, the ventilation requirement is met with an operable window,” says the president of the Albanese Organization, Russell Albanese, whose firm developed the Solaire and the Verdesian. Their current project is the Visionaire, another development with a nifty name, which will be constructed within the next 20 months.

Many green residences exceed local requirements, as air is stripped of pollutants, allergens, and other potentially harmful materials before it enters the building. Both the Verdesian and another nearby Battery Park City development, the Riverhouse, humidify air in the winter. This also tends to be a major selling point: “One of the most important features to the consumers is air quality,” Mr. Albanese said.

One unifying theme of the latest earth-friendly technologies seems to be that if there’s a will, there’s a way. When it comes to conservation, planners have found ways to reuse natural resources. “As with many things in green buildings, it applies an old principle to a new construction,” Mr. Pelli said.

At the Riverhouse, waste emanating from toilets and sinks (referred to as blackwater by the industry, and pooh by little tikes) is purified and then recirculated to the toilets. “All of the blackwater goes through the two-filter system and comes out almost drinking quality,” the project manager of Ismael Leyva Architects, Bhaksar Srivastava, said. Almost? The director of design and construction for the Sheldrake Organization, which developed the luxury condominium, is even more outrageous.”I just took a sip of it,” says Glen Ravn, and assures that it is indeed of drinking quality. We’ll trust him on that one. Enjoy the rest of your beverage!

Conservation methods are also in place for water that has not yet entered the tower. “We harvest a lot of the rain water and hold it in a tank to water the gardens,” Mr. Pelli said of the Verdesian.

Solar energy is also harvested, mostly through strategically placed “photovoltaic cells” on rooftops. The cells, which can be thought of as oversized versions of those found on calculators, store the sunlight and then use it as a partial electrical source for the building.

To maximize efficiency, cells at the Riverhouse automatically rotate towards the sun (much like I do on my beach towel).

Electricity is further conserved, so they claim, by sensors that detect a building’s lighting levels. We’re talking Star Trek here. On days when sunlight pours through the Riverhouse’s windows, the sensors automatically dim the electrical bulbs. Once the sun sets, which it always seems to do, the bulbs function at maximum brightness.

What is not surprising is that the non-profit sector has caught on to this phenomenon. “The market is evolving and it’s sort of a scary place to be, but we’re on the vanguard of green marketing,” the Habitat for Humanity NYC’s executive director, Roland Lewis, said.

At a Mott Haven residence being constructed by Habitat for Humanity, a national organization that provides homes to impoverished families, recycled blue jeans line the wall interiors as a form of insulation. At the Halsey Street project in the Bedford Stuyvesant section of Brooklyn, insulated concrete forms — styrofoam pieces sandwiched between sheets of steel and concrete — are the latest technology used.

Sustainable architecture has also infiltrated the world of commercial real estate. Along with light sensors and high-efficiency heating and cooling systems, 7 World Trade Center also has detectors that monitor levels of carbon dioxide in the air.

If these benefits don’t come at a cost to your health, they certainly have the potential to sock you in the wallet. Compared to a “non-green” building of a similar size, the construction costs for a residential tower are anywhere between 5% and 10% greater, industry members approximate .

According to Mr. Albanese, the differential for commercial buildings is about 1%.

Even though tax credits for green buildings are in place, they are not quite as advanced as the available technology. For the $35 million that the Sheldrake Organization will use to construct Riverhouse, they expect to receive about $1 million in return, Mr. Ravn said.

Still, say industry members, the benefits far outweigh the costs. “We talk about green architecture, but it’s really about higher building standards,” Mr. Pelli said.