The Belfast Cohousing and Ecovillage, a unique development just two miles west of downtown Belfast, held an event Sunday to celebrate the completion of its first six units. Those units will be filled this week, kicking off life in a neighborhood that aims to be a model of both community planning and environmentally conscious building.

The development will eventually have 36 units, of which 25 have already been sold. They range in size from 500 to 1,700 square feet and can cost between $150,000 and $330,000.

Sanna McKim was part of the original group that has been developing the Ecovillage since 2007 and is a future resident. She noticed that the farmland the neighborhood is being constructed on was up for sale five years ago. Since then McKim and a core group consisting of several local families began to draw up a mission for the development.

“Community is the secret ingredient to sustainability,” McKim said. “Distance makes sharing and conserving so much harder.”

The group decided to follow a model imported from Denmark called cohousing to help in the design of the neighborhood. Cohousing uses tightly clustered homes, common spaces and shared activities to bring the neighborhood together.

At the Ecovillage a large common house — in addition to the individual units — will be constructed over the next year that will house play areas, guest rooms, a kitchen and eventual office space. Each resident will be responsible for cooking for the community around one meal a month. There will also be community gardens, orchards and possibly a barn, said McKim, who owns a pony that made an appearance at the event Sunday .

The neighborhood sits on 42-acres, of which more than 80 percent is conserved for open space or farming. It will also include a diverse group of residents, some coming from as far away as Austria and California. However, most of the future residents live within an hour of Belfast, said McKim.

Like in a condo association, each of the members has a say in how the common areas and exterior of the buildings are managed. People interested in joining Ecovillage have the option of becoming members for six months.

Passivhaus

Another key aspect to the Ecovillage is its use of Passivhaus design. Passivhaus is a German concept that uses extremely well insulated homes and solar heat gain through windows to reduce energy consumption by around 90 percent, compared to a house built strictly to code, Alan Gibson, the project’s builder and McKim’s husband, explained.

“These houses are pretty extraordinary in and of themselves,” said Gibson, who co-owns G•O Logic, a Belfast-based architectural and building company. “After 30 years living here you could save around $100,000 in energy costs.”

When a home is paired with grid-connected photovoltaic and solar hot water systems — an option for all the Ecovillage homes — it can become a “net zero” home, or a home that uses no net power. The cost of the solar energy systems is around $15,000 after tax rebates and pays for itself in around 12 years, said Gibson.

Each home sits on an insulated concrete slab foundation and has super insulated walls that are around 13 inches thick, said Gibson. The units are nearly airtight and use a ventilation system that brings in fresh air, while capturing the heat of the indoor air.

Each of the windows and doors is imported from Germany and is three panes thick. They are situated to face south, whenever possible, to collect the most heat from the sun. Each unit will cost around $200 to heat for the entire year, said Gibson.

“People like living in well insulated homes,” Gibson said. “They are more comfortable and they cost less.”

Gibson admits that the homes cost more than a comparably sized unit would, but says the energy savings and common areas in the neighborhood more than make up for the added expense.

The neighborhood will continue to take shape over the next year. Three more units will be ready in July and several more will be completed in the fall. The development has taken time to set up, but now that construction is under way, McKim says she hopes the units that have already been sold will be finished within a year and a half.

“We’ve hit our groove now,” McKim said. “We’re just excited to see this happening, because we love Maine and we love Belfast.”