ARVADA - Geos, a new mixed-use neighborhood being built in Arvada, sets a new standard for energy-efficient, earth-friendly communities.

The 300-unit neighborhood will be the first in the country to sustain itself using only alternative energy sources, not fossil fuels. Geothermal heating and cooling technologies, photovoltaic panels, ground source heat pumps, passive solar design and efficient building practices combine to give future homeowners an opportunity to live comfortably without paying energy bills.

For those who want to live with less impact on the environment, "Geos will speak to things that are central to people's lives," said David Kahn, president of David Kahn Studio in Eldorado Springs and co-master planner with Denver-based Michael Tavel Architects, "such as their resources, their interaction with the landscape and stewardship, and being conscious of their place in the larger picture."

Geos will consist of four subneighborhoods. In the Checkerboard Blocks Neighborhood homeowners will use passive solar heating in the winter. Units are staggered in a block-and-alley system to take advantage of the sun, Kahn said. The design is not unusual, but, he said, they brought in help from the National Renewable Energy Laboratory in Golden to conduct energy modeling and ensure the design maximizes passive solar gain for each unit.

Norbert Klebl, master developer of Geos, drew on the European Passive House Energy Standard in planning for the self-sufficiency of the units in Geos. This standard results in homes that save 80 percent of the energy used by a typical new home. One of this standard's innovations is to tap into the constant ground temperature of 50 to 55 degrees that is found five to seven feet below the Earth's surface. Both the domestic hot water and the heating and cooling of each Geos unit will draw from this source.

Each unit will have photovoltaic panels tied to the electric grid, so if the home's panels generate more energy than the home uses the excess will be fed into the grid. If owners use less energy than what they draw from the grid, which is what the Geos team anticipates, then homeowners will have no energy bill.

An airtight design, high-performance windows and insulation also help decrease the need for energy use in each unit. The Geos team estimates that what homeowners save in energy costs will balance out the additional cost of each unit's alternative energy technologies.

The Geos team aims to make the neighborhood not only sustainable but also people friendly. Parks, plazas and trails will make up 40 percent of the neighborhood. Many of the established cottonwood trees will remain in place, community gardens will be available, and percolation parks will provide water for landscaping and will help naturally filter storm water. The neighborhood also abuts the Ralston Creek Trail, which is part of the Denver Regional Bike Trail System, so residents will have bike access to the APEX Recreation Center, among other destinations.

In a joint venture with Norbert Klebl, Boulder-based Wonderland Hill Development Co. will build at least half of the units in Geos, said Jim Leach, Wonderland's president.

Wonderland Hill is known for its sustainable, people-oriented communities: Solar Row and Silver Sage Village, in Boulder, and the Lyons Valley Village in Lyons.

Leach is most excited about the community aspect of Geos.

"Our company specializes in doing community-based development, where we see community as an important part of sustainability. Geos will be a real prototype of the kind of neighborhoods and developments we're going to see in the future, as a replacement to the prevailing suburban model. This will be a model both in terms of how residents can live a more sustainable lifestyle and how a new neighborhood can really work."

At the heart of Geos, Wonderland Hill will be constructing a co-housing community, he said. As part of this community there will be a common house that will be available for other residents in the larger neighborhood. Billed as "the biggest living room in the neighborhood," Leach said it will likely become a focal point for the neighborhood in addition to being a feature of the cohousing community.

The net-zero-energy units in Geos range from single-family homes to town homes to co-housing units. Commercial and live/work units will also be available. Prices will run from $180,000 to $540,000. The Geos team has recently submitted their final development plan and expects to begin constructing the infrastructure in a few weeks. Units are projected to be available in the spring of 2009.

The Geos project has already won the 2006 American Institute of Architect's Denver Honor Award, the 2006 AIA Colorado Citation Award and the 2006 Denver Sustainability Award.