WOODED SETTING: With its sod roofs and harvesting of rainwater, the new Copperwood development of rental units is big on sustainability. Eighty percent of the apartments are designated for active adults over 55; and another 20 percent can be rented to younger tenants. Twelve of the 150 units are designated as affordable housing. (Photo by Tom Grimes)

After 10 years of deliberations, environmental considerations, and reconfigurations, Copperwood, the rental community on Bunn Drive, has officially opened. Thirty of the 150 units set among the trees have been rented, and there has been “a huge uptick in interest” since the ceremony last week, said architect and developer (and Town Topics shareholder) Bob Hillier.

The project dates back to 2003, when senior housing was first proposed for the Princeton Ridge. Two years later, developer K. Hovnanian was approved to build an age-restricted complex on what was known as the Lowe tract. But the developer withdrew its application after a public outcry over plans to disturb nearly 80 percent of the environmentally sensitive site.

Environmentalists sued what was then Princeton Township over the zoning that allowed any development on the Ridge. Mr. Hillier stepped in and redesigned the project for a much smaller footprint, clustering five buildings on three acres of the 21-acre site. The remaining lands were put into conservation in perpetuity.

“I’m especially proud of the sustainability aspects,” said Mr. Hillier, referring to a three-acre detention basin that was part of the original plan and was eliminated. As part of the project, the Princeton Community Village detention basin across the road was improved, which in turn helps prevent flooding at the Governor’s Lane development, he said.

Copperwood is designed around a system of piazzas and garden walkways. Its green features include the facades of the buildings, colored to blend into the wooded site and made of reflective materials to repel the heat of the sun. Among Mr. Hillier’s favorite features are the 12-foot ceilings in the living rooms of some of the top-floor units. “They’re just breathtaking,” he said.

Speaking at the opening ceremony, Mayor Liz Lempert called the buildings some of the most sustainable in Princeton. She added, “It’s gratifying to be standing here today in front of a project that so many of us can celebrate as a victory — the senior housing advocates, the environmentalists, the developer, and the community. It is a prime example of the power of collaborative efforts, and will serve as a model for how to successfully work together to build a more sustainable Princeton.”

Mr. Hillier said this week, “We were able to get a lot of cooperation from the town, including the building department, which I’m grateful for. I’m relieved and proud and glad that we now have a place in Princeton where people can downsize, which they couldn’t before.”