Currently, buildings contribute 39% of anthropogenic carbon emissions in the atmosphere¹, and hence it is critical that designers work towards developing net-zero systems by considering the amount of embodied carbon in material selection, construction, and maintenance. By 2030, more than 43% of carbon emissions will need to be curbed to stay below 1.5C of global warming². By 2050, we must reach zero emissions!

Furthermore, eighty percent of the buildings in 2050 already exist today³. Strategic renovations and upgrades can thus be applied to much of the current building stock. New buildings must be designed to last well into the future, making adaptability and resilience top priorities. This means that they must be energy efficient and produce their own electricity, and generate no carbon emissions.

There are a number of approaches to achieve net-zero design, including: adaptive reuse and energy efficiency upgrades for existing buildings and the use of renewable materials like mass timber for new construction⁴.

With adaptive reuse and energy efficiency upgrades, buildings can be tailored to new uses and their lifespans can be extended without requiring complete demolition, hence shrinking costs. Whilst reducing the embodied and operational carbon footprint, they can also improve the character of a neighborhood.

fig.1: picture by thermal camera showing where heat is leaking out of walls and windows; fig.2: transformation of the Grand Parc estate in Bordeaux by Lacaton & Vassal, Fréderic Druot and Christophe Hutin

Process of Net-zero design

When we work on new buildings we believe in designing from the inside out. First, we work with the client to deeply understand their program, needs, and constraints. We then look to design high-quality spaces with good daylighting, acoustics, and views. We organize these program elements with logical layouts, and clear circulation and prioritize low form factors for the exterior. Organization to work with environmental factors (sun, wind, and topography) and local site issues is a must.

Whole-Building Energy Modeling (BEM) provides an accurate basis for informed decision-making on issues such as orientation, massing, percentage of glazing to solid walls, and system selection. Daylight analysis can provide input to maximize the quantity, quality, and usage of natural daylight within the building. Life Cycle Assessment (LCA) provides input into the potential environmental impacts of systems over a range of metrics including global warming, acidification, eutrophication, and ozone depletion⁵.

One approach for a building's structural system is mass timber, composed of multiple solid wood panels that are nailed or glued together, providing exceptional strength and stability. It’s a low-carbon alternative to concrete and steel, also providing fire resistance when used with larger member sizes. Because trees absorb carbon, mass timber sequesters carbon from the atmosphere instead of adding to it.

The key drivers for the design are reducing the quantities of embodied and operational carbon created during the construction and life of a building. Strategizing at the outset of the project can mitigate potential additional costs and lead to higher-quality environments which are a stronger asset for the client.

fig.3 & fig.4: Cristalleries Planell Civic Center by H Arquitectes as an adaptive reuse project of the heritage-listed frontage of the former Planell glass factory, built on Calle Anglesola in 1913