In the competitive business of selling condos, flashy features like floor-to-ceiling windows and granite countertops are classic ways to convert a ditherer into a buyer. Back in 2006, when the Toronto Community Housing Corporation (TCH) issued a call for proposals for a condo development that would lead the redevelopment of Regent Park, The Daniels Corporation's Martin Blake realized that it would take more than bells and whistles to make the project work.

The criteria for the redevelopment of Regent Park -- which, over 10 years, will replace the rundown and ill-reputed 1940s social housing buildings with a modern mix of rent-geared-to-income and market-value housing, as well as commercial and community amenities the area has always lacked -- were strict. TCH not only wanted its own rental buildings to raise the bar for environmental sustainability (and so save itself money in the long term), it wanted Regent Park's for-profit developments to be green, too. And each project would have to pass the muster of a design review panel.

When it won the contract for phase one that included four high-rises and five townhouses, The Daniels Corporation received a set of guidelines that had made other developers balk. The condo project One Cole, made up of 293 residential units plus a Sobeys, an RBC and a Tim Hortons as retail anchors, was required to be LEED Gold. Short for Leadership in Energy and Environmental Design, the internationally recognized certification demonstrates that the builder has taken extra measures to make the building energy and water efficient and eco-friendly. Initiatives like dual-flush toilets, energy-efficient lighting and state-of-the-art heating and cooling units drive up the cost of building, but are traditionally are not seen as the most effective consumer enticements. In the case of some LEED Gold criteria -- like limiting the amount of glass used in the building in order to reduce heat loss, so bye-bye floor-to-ceiling windows -- the results can turn some buyers off.

"The challenge is getting people past the granite countertops," says Blake, vice president of project implementation at Daniels. "We really had to clear the decks and make sure it was head and shoulders above anything else you could buy."

One Cole, which officially opened for occupancy this summer, not only sold out quickly, it won a Green Toronto Award for its design and helped Daniels win the contract as partner for the rest of Regent Park's 69-acre redevelopment. For Daniels and Diamond+Schmitt Architects, the strict rules weren't just a headache -- although they sometimes were that -- they were an opportunity to push the limits of what they could squeeze into a building without sacrificing the flash.

"The thing we're most proud of is that the energy efficiency is 43 percent better than the national model building," says Blake. "But we spent a lot of time making sure people don't see any difference. Their carbon footprint is dramatically reduced but, in the suites, they don't even notice."

What residents do notice are the two dramatic lush green walls, one in the amenities area, one in the Sobeys store, which regulate and filter air flow, and the massive third-floor skypark which has 40 trees planted in five feet of soil. These feats of engineering had to be accomplished on a tight budget, considering unit prices started at $189,000. The location wasn't Rosedale or another neighbourhood where people pay a premium to live, but an emerging new neighbourhood that was not yet defined.

"Even without the LEED Gold, the building had to have special features," says Robert Boyd, lead architect for Diamond+Schmitt. "It had to make people believe in Regent Park, to really demonstrate that it was a viable community." That meant a handsome building that feels of-the-moment but also recognizes the area's history in its red-brick cladding, a building that scaled well to its surroundings and a building that created community and safety by placing eyes on the streets, with townhouse doors and windows in unexpected places.

The tension between TCH's idealism and Daniels' need to not lose its shirt resulted in some innovative compromises. The guidelines required the underground parking garage to have a smaller footprint than the building itself, so the trees would have enough room to grow proper root systems, says Boyd. But that would have meant losing parking spaces and profits. The approved design found a way to make room for both cars and trees.

There were not only the usual rules about the building's height, but rules about how many storeys it could contain. Daniels was able to convince TCH that it could add another floor -- with more units to sell -- while maintaining nine-foot ceilings.

"I think we really learned where to squeeze and where to give," says Boyd. "For example, there's a bunch of overhead doors and louvers on what is essentially the back end of the building. They pushed us hard to make it as elegant as possible, even though you wouldn't expect it there. It was important that the building was integrated into the streetscape."

In the beginning, none of One Cole's successes were taken as a given, says John Fox, vice president of development at TCH. The city corporation works with developers on a regular basis, but this kind of risk-sharing and custom-building was brand new.

"The concern with 'Can we even do this?' is gone," says Fox. "It shows that you can sell a green building in a new neighbourhood."

While Blake and Boyd are proud of how the building looks and works, Fox is most proud of how One Cole's residents are already engaging in their new mixed-income neighbourhood, helping to shape the rest of the Regent Park revitalization.

"The city is currently holding a consultation on what people want in the big park that will be in the middle of Regent Park," says Fox. "You can see the residents from One Cole at the table, along with the rest of the neighbourhood. They have a real interest in integrating themselves into the community."