When Andrew McMullin, a contractor in Boulder, Colo., wanted to build an off-the-grid house made of shipping containers, on a rock outcropping 9,000 feet above sea level, he turned to a local firm named Studio H:T Architecture. Founded in 2005 by Christopher Herr, AIA, and Brad Tomecek, AIA, the studio had developed a reputation for its cutting-edge design using sustainable, innovative materials. But Herr and Tomecek had never worked with shipping containers.

For McMullin’s house, just outside the funky mountain town of Nederland, the architects placed two shipping containers side by side, about 12 feet apart at one end and 20 feet at the other, creating a wedge-shaped space in between for a living and dining area. They insulated the containers from the outside and clad them in fireproof, horizontal plank siding. In one container they designed a kitchen, an office, and a laundry room; in the other, two bedrooms. Photovoltaic panels on the roof provide electricity for the 1,500-square-foot dwelling, and winter heating comes from a pellet stove. The house is aligned to take advantage of Colorado’s abundant sunshine, which is absorbed by the living room’s concrete floor during the day (via two garage-door style windows) and helps heat the house at night.

You can’t see Shipping Container House from the main highway that runs through Nederland, but the structure has been widely published—in newspapers, magazines, and on websites. And for good reason: It is, in a word, stunning. One end of the house perches delicately on the rocks, while the other, wider end seems to stretch toward the surrounding mountains. “We call it the ‘origin’ and the ‘echo,’ ” Tomecek says. “The house is really a dialog between those connecting elements.”

Shipping Container House was completed in 2010. And given the buzz it generated, Herr and Tomecek could probably have turned Studio H:T into an all-shipping-container, all-the-time practice. “But we didn’t want to be pigeonholed,” Tomecek says. Indeed, he and Herr have been known to push back against prospective clients who want their own version of Shipping Container House. “We grill them. We ask, ‘Why containers? Do you really love them?’ We explain that they can be really loud, and you’re probably not going to save money by building with them. If they’re willing to go for it, and really want to try something different, we’ll work with them. But we don’t go around saying, ‘Container, container, container!’ ”

“Some architects practice in a particular style,” Herr says, “and there’s nothing wrong with that. But that’s not what we do. We ask and answer a series of questions about the site, the client, and the program. And that’s what leads to the architecture.”

Working out of a small office in downtown Boulder, Herr, 43, and Tomecek, 40, have been honored with dozens of regional AIA awards for their growing portfolio of residential and commercial projects, most of them located in Colorado. Each has won the AIA’s Young Architects Award—Herr in 2011, Tomecek in 2012.

These days, they’re busy juggling multiple projects, including a multifamily development in Denver (Framework at Sloan’s Lake) that just broke ground, and an 11,000-square-feet, net-zero-energy house on the plains northeast of Boulder. They recently hired two additional architects, bringing the total number of employees to seven. “And we probably need to hire one more,” Tomecek says.

In person, Tomecek is friendly but intense, a self-described “big picture” guy who in conversation tends toward the abstract. Herr comes across as more down to earth. “I’m more interested in details,” he says, “so it makes for a good collaboration.”

The architects met as graduate architecture students at the University of Florida in Gainesville. Herr, a Colorado native, had gone to pursue a degree in acoustics—he plays the French horn and has an undergraduate degree in music performance from the San Francisco Conservatory of Music. (His favorite composer: Gustav Mahler.) Tomecek, born in Hollywood, Fla., was interested in music of a different sort: heavy metal. “Total hair bands,” he says. “Not that I’m looking to emphasize that.” What brought them together, Tomecek says, was a shared “hyper passion” for design, and their conviction in its power to transform lives.

After graduate school, Herr settled in Boulder, where he worked for several local firms. Tomecek considered moving to Austin or Phoenix, but when he visited Herr in Boulder, a university town set against the foothills of the Rockies, he fell in love with the place. “I went camping, rock climbing, and snowboarding,” Tomecek says. “I said, You know what? I’m moving here. This place rocks.”

Eventually, Herr and Tomecek decided to form a partnership, with $600 in the bank. They rented a one-room office in a red-brick building on Boulder’s Pearl Street pedestrian mall.

Eight years later, the firm is still there, in a slightly bigger office down the hall: a single room with an adjoining windowless conference space that overflows with wood and cardboard models of their work. There are no cubicles and no room dividers. Tomecek admits that space is tight, “but at the same time, it’s very open and very collaborative. It’s not like I’m always behind a door and you have to knock to come in.”

One of the partners’ first projects together was Box House, a home for Herr and his family. The 2,300-square-foot house was built on a steep parcel of land in Boulder that had been in Herr’s family for years. The construction process was documented by both HGTV’s Dream House series and the Rocky Mountain News. (The media attention helped put Studio H:T on the map.) In keeping with Herr and Tomecek’s interest in green design, the house has walls made of structural insulated panels, in-floor radiant heating, and solar photovoltaic panels that produce 85 percent of the home’s electricity.

Since then, they’ve created something of a niche for themselves by designing energy-efficient houses on challenging urban infill lots. For example, in Denver’s hip Highland neighborhood, where the lots tend to be long and narrow, a client wanted some privacy from the three-story triplex next door. Herr and Tomecek’s solution: a two-story structure with a curved metal wall that “shields” the house from nosy neighbors while also serving as a striking visual element. (Fittingly, they dubbed the project Shield House.)

A few blocks away, the firm built Tomecek’s own wood-frame house on a narrow lot as an exploration in modular construction. The structure was assembled in a factory north of Denver in just three weeks and then lifted onto the property (125 feet long, 25 feet wide) by crane, in two pieces, one for each floor. Once in place—on top of a poured-concrete foundation—the exterior walls were covered in stucco. Ingeniously, the floors are offset lengthwise, creating a deck off the second-floor master bedroom and a covered rear entry on the ground floor. A separate garage was built on site. The house, called 32nd Street Modular, earned LEED Silver certification.

Also in Denver, the firm was hired to design an addition to a small commercial sign business located in a former motorcycle repair shop. The only stipulation from the client, who contacted Studio H:T after seeing Shield House, was that he couldn’t close his business during construction. That led Herr and Tomecek to “wrap” the addition, made of rusted steel panels, around the existing brick structure.

In one of their more ambitious partnerships, the firm worked with Vireo, a Boulder-based developer, to design a multimillion-dollar “eco-hyperluxury” home. Built on a steep hillside in Boulder and completed in 2010, the 4,679-square-foot house incorporated energy-efficient, wood-based, hypo-allergenic panels made by WeberHaus, whose factory is based in Kehl, Germany. Tomecek says that Vireo intended to use the house as a showcase for its plans to open a U.S. factory modeled on the German company. But the recession hit, Vireo went under, and the house sat on the market for several years.

It recently sold, and on the day I visited the house—named for its address, 2002 Alpine—with Herr and Tomecek, we met the new owner, an American chemical engineer who had spent two years living in Geneva, Switzerland. “This is the house for an engineer,” he said. “I love the design and the way it’s constructed.” The house, with its superinsulated walls, is projected to use just 18 percent of the energy of a typical American home. “I think the electrical bill will probably end up being about $10 a month,” he said.

Next door, on a similar property, Herr and Tomecek worked with another developer to design a dwelling they call Fractured Residence. Like the Shipping Container House, it is splayed—one end is wider than the other—and the architects broke up the open interior space with irregular, sharply angled supports and railings. Unlike the boxy 2002 Alpine house, it was built using conventional stick-frame construction, which allowed Herr and Tomecek to forgo traditional right angles. Think of it as the flamboyant neighbor to the Teutonic dwelling next door.

I asked Herr and Tomecek if there’s a connecting thread that runs through their diverse body of work. Certainly it’s not a particular visual style, though there are aesthetic similarities among their buildings. And it’s not a particular material, either. (“We don’t think that prefab is a global savior,” Herr says, “and we don’t think that stick-frame construction is at the end of its lifespan.”) Clearly, sustainability is a common element, but they resist the “green” architecture label because it’s merely a starting point for everything they do. (Herr and Tomecek both have LEED credentials.)

“I think what underpins our work is a progressive series of investigations,” Herr says. “It’s all about looking at alternative methods of construction in a quest for the right system for the job. So there’s a common thread of systems exploration, combined with thoughtful interaction with clients to address their needs.”

And while Herr and Tomecek resist labels, they concede that there may come a time where they won’t have to start from scratch every time they begin a new project.

“We’ve done a lot of projects that are very one-off and unique,” Herr says. “We’ll probably hit a point where we say to ourselves, ‘OK, these are the things we want to continue with, whether it’s a material, or a manufacturer for a window, those types of things.’ But we’re not there yet.”