Six weeks after moving from a “gorgeous custom house with huge gardens” in a suburb of Auckland, New Zealand, into an apartment a few minutes from the city’s central business district, Roz Mawson couldn’t be happier. (Nor could her two children, who had flown the nest until they set eyes upon their mother’s cool new digs.) “It was time to take ourselves out of our comfort zone, to excite ourselves again and try a way of life that doesn’t revolve around the car. Now I walk to cafés, shops, the fishmonger, yoga. And from my balconies I feel part of humanity—I can see joggers, the ferries across the harbor, and people walking their dogs in the Domain.”

Mawson’s perch is from a penthouse flat in Trinity Apartments, a six-story, three-tiered complex that sits atop a ridge in the trendy Auckland neighborhood of Parnell. Facing the historic Holy Trinity Cathedral across the road to the east, and the undulating landscape of the park known as the Auckland Domain to the west, it’s a breath of fresh air for several reasons. In an upscale area of shops, cafés, galleries, and single-family terrace homes, where precious few apartment blocks have gone up since the ’70s, the site granted lead architect Patrick Clifford of Architectus—a firm known for its environmental sensitivity—an opportunity to reintroduce high-density living with a difference. The concrete, glass, and cedar structure with 32 roomy apartments (ranging from 750 to 2,350 square feet) is not only striking to look at, but engineered to harness natural light, warmth, and an abundance of cooling breezes.

Essential to the year-round temperature regulation is the building’s high thermal mass—“like a monolithic concrete egg crate filled in with glazing,” explains Clifford—which retains heat in winter while deflecting it in summer. In the dead of winter, Mawson has little cause to turn the heat on during the day. “We keep our huge sliding doors open and Otis, our 14-year-old French bulldog, basks in the sunlight.”

In this country of outdoors enthusiasts, meticulous attention was paid to the transitional areas, with unusually large verandas and balconies (325 to 1,075 square feet) that encourage cooling cross drafts and relieve the extreme humidity. True outdoor rooms, these spaces shelter from the rain and intense sun with shading devices made variously of glass, plantation cedar, and aluminum, which not only harmonize with their immediate surroundings but create an interesting horizontal and vertical rhythm around the building. Along the urban street edges, vertical glass louvers are backed with rolling solar blinds; their sculptural, blade-like fins cast beautiful reflections onto the street and provide residents with a subtle privacy screen. Wooden shutters close off the garden-facing balconies, in keeping with the more domestic feeling in the back. And up top, horizontal aluminum louvers keep the set-back sixth-floor bedrooms cozy. “One of the things that attracted us was the way the building looked,” says Mawson, whose former home was a classical 1920s house. “New Zealand got hooked for years on this sort of quasi-Mediterranean style,” she continues. “Here there’s an understated rawness that will endure; it’s both comfortable and alive.”

Where most apartment blocks are boxy, fortresslike structures with a single entrance, Trinity is layered in levels, which increases air flow, and has two transparent, timber-paneled lobbies, one of which connects the street to the garden. These throughways also act as huge vents, pulling warm air in and up the light-filled atria, which frame views of the garden and cathedral on each level. “It’s a more humanistic alternative to the artificially lit, carpeted hallway with white plasterboard,” says Clifford. “And it encourages you to take the stairs.”

Because the building was taken right to the edge of its two boundaries, says Clifford, “rather than pulled in with the usual line of defense between building and street,” it allowed for the largest possible garden within the resulting L shape: an unusual 50 percent of the lot (with underground parking concealed below). One walks straight through the building onto a boardwalk and over a reflecting pool, which, together with the lap pool, helps temper the air through evaporative cooling, as does the presence of so much plant material. Here, too, landscape architect Matthew Bradbury sought to provide a personal haven for residents that relates to the wider world: “Gardens are traditionally these private pleasure zones,” says Bradbury, “but I think it’s also possible to transcend the borders.” Oak trees planted on the sidewalk along the front of the building relate to those found in the English colonial-style plantings around the cathedral, while the lawn in the back drops down to a garden lush with many of the native species found in the park beyond: “It’s as if the garden were leaping over the fence,” says Bradbury.

As for Mawson, the transition from suburban house to city flat has had multiple rewards. “I’m so enjoying culling our furniture. What is it about nesting habits that makes us accumulate so much stuff?”