How New Zealand firm Warren and Mahoney integrates climate, culture, and data

New Zealand architecture firm Warren and Mahoney is using digital design tools to meet an ambitious sustainability goal: to make all of its projects net zero by 2030, consuming 40% less embodied carbon compared to comparable buildings of traditional construction.

But getting to net zero goes beyond technology choices and digital models. “We must seek to learn from people who are more attuned to the climate and our relationship to it and use technology to create data-informed, climatically responsive architecture,” says Fiona Short, lead of sustainability at Warren and Mahoney. “[This means combining] high-tech measurement and modeling with a deep local understanding of the climate and materials. The best design response is unique to place. You start to get this deep reflection of place represented in zero-carbon architecture, which I like to think of as a zero-carbon vernacular.”

Premodern and indigenous cultures built without using carbon-emissions-intensive energy and were masters of ecological vernacular design languages across the globe. Their descendants and built heritage still hold this knowledge, and adopting similar techniques and elements of their ecological worldview could help mitigate the growing effects of climate change. This takes on new meaning as leaders of the developing world excoriate rich nations at the COP27 climate change conference in Egypt for their culpability in producing the carbon emissions that cost poorer nations billions of dollars and thousands of lives.

In New Zealand, the Maori people developed knowledge of how to live as a conscious part of an ecological system. Warren and Mahoney is learning to look to indigenous knowledge of sustainability, formal expression, and ecological balance to improve environmental outcomes and connect people with place through storytelling and formal expression. Short asks two key questions of all her projects: “What is the carbon story of this project?” and “What is the story of the people and place?”

A project’s “carbon story” refers to all carbon emissions: those caused by the embodied carbon contained in all components and materials from their manufacturing, transportation, and installation, as well as the emissions from the project energy consumption, called operational carbon.

To estimate embodied carbon, Warren and Mahoney is using Autodesk Revit to create a digital twin that is then measured using One Click LCA, which allows teams to reveal the global-warming potential for alternative designs, as well as building elements: roofs, facades, windows, doors, and so forth. This data tells each building’s carbon story unique to its materials and design.

One project, The Domain Collection luxury apartments in Auckland, New Zealand, illustrated that the decision to reuse a concrete structure would avoid the emissions of approximately 1,400 tons of carbon. Understanding this meant the design team could talk about the impact of their design decisions. They decided to reuse the structure, which saved the carbon equivalent of driving from Los Angeles to New York 2,000 times, and earned cost savings.

“We found that having those insights has been incredible because it suddenly reveals lots of opportunities to decarbonize,” Short says. “Through this adoption of high tech as part of our design process, we can now make data-informed designs decisions at the right time, which will lead us to more climate-conscious design and toward our net-zero carbon goals.”

New Zealand’s geographic position as an island in the global south positions it uniquely in the matrix of embodied and operational energy costs. Eighty percent of the nation’s electricity is generated from renewable sources, so carbon emissions from building operations are a fraction of those in the United States, for example. But because New Zealand is far away from most building-component production, materials are often shipped vast distances, making embodied-transit carbon emissions higher. Additionally, the type of iron found and smelted in New Zealand to manufacture steel (derived from iron sand rather than iron ore) requires more energy and thus carbon emissions to refine.

To lower the carbon of its designs, Warren and Mahoney is leaning more heavily into the use of mass timber. Currently, Short is working on a hybrid mass timber and concrete building project, the He Toki Kai Te Rika Otago Polytechnic Trades Training Centre in Dunedin, New Zealand. The basement is concrete, and everything above that level comprises cross-laminated timber (CLT) and laminated veneer lumber (LVL). The mass-timber structure stores 630 tons of sequestered carbon—the equivalent of 10 years of growth of 10,000 planted tree seedlings.

Another sustainable building strategy Warren and Mahoney uses is passive design, which means “using the form of the building to improve comfort and energy efficiency rather than relying purely on mechanical systems,” Short says. Passively attuning a building to its climatic conditions means considering the orientation of building design and elements to modulate daylighting exposure, natural ventilation, and placement of thermal mass, as well as insulation to reduce energy demand before planning for any active systems or energy-generation strategies. “The best designs end up as a really interesting combination of passive design strategies and a high-tech understanding of it through analysis,” she says.

Deploying low-tech passive design strategies can align designers with building forms that are more closely tied to the culture as well as the climate of a place. For Short, this means leaning into the Maori concept of Kaitiaki: a commitment to ecological guardianship, protection, and conservation.

In practical terms, this means collaborating with the local Maori people who have mana whenua status (authority over the land) to understand and respond better to the natural, cultural, and sacred history of the place. There are also many examples of traditional building techniques that respond to the climate, which designers can look to learn from and apply to the contemporary built environment.

“One simple example that I quite like is if you go to an old pā site, which is a traditional Maori village, there’ll be numerous pits dug into the ground,” Short says. “It’s used to store food at a stable cool temperature, similar to a root cellar. Maori used the mass of the ground to extract the heat out of the space so you can keep things cool with a small structure over the top to keep it shady. This passive design uses ventilation and mass to maintain a suitable temperature for vegetables but also can be applied as a design strategy to keep an environment comfortable for people.”

Place, culture, and history also influence design choices. One project, due to be completed by 2026, is the Heke Hua Archives New Zealand building in Wellington. The formal expression has been co-designed with Maori mana whenua representatives and design agency Tihei working alongside Warren and Mahoney and DIA to articulate a Maori world view. The building will store more than 7 million records and national treasures (aka taonga to the Maori people).

Because the building will sit on the historic site for the Pipitea Pā, predating the European settlement in Wellington Harbour, Warren and Mahoney took care to tell the story of the indigenous people in the building design. “That building has had a really successful engagement process where a lot of the stories of the site, and the treasures it holds, are expressed in the design of the facade, working with artists to tell those stories through patterns and form-making of the facades,” Short says. “When you look at the building, you can start to understand the stories, why it’s there, what it holds, and what it means to people.”

Due to the nature of the treasures housed in the building, the environmental performance for heat and humidity is paramount. The building uses a combination of a highly tuned building fabric and advanced active systems to ensure the contents are protected for generations to come. Like the food storage pit, Heke Hua Archives utilizes exposed thermal mass to maintain a stable environment and reduce the use of mechanical air conditioning.

As Short and Warren and Mahoney look more extensively into the indigenous ways of building, it becomes more apparent that the carbon story of a building and the story of the people and the place are really two sides of the same coin. “When we design in response to the climate, we inherently get buildings that are low carbon,” Short says. “The stories of place can ideally inspire the whole concept of the building, how people might use it, and how people would relate to it.”