Net Zero Energy (NZE) was once the holy grail of sustainable building design—enticing, but often out of reach. That has all since changed.
Giant leaps in net zero design such as improved materials, a better understanding of building science, and cheaper renewable energy have made NZE buildings a viable and affordable goal for building owners.
Take the example of K-12 schools: Back in 2017, SMMA had just one net zero school project in our portfolio. In 2022, five years later, we have six schools that are net zero ready. This underlines how NZE has become a more realistic and serious goal, precisely because it is easier to do.
SMMA used this exact approach at The Lincoln School, Massachusetts’ first ever net zero school renovation. Partnering with net zero specialists Maclay Architects, we redesigned the exterior walls and roof envelopes to allow for deeper insulation. This resulted in a 48.1% carbon reduction.
2. Harvest Site Energy
Harvesting “free” energy is a no-brainer for building owners in any context. But when aiming for NZE, the approach takes on a whole new importance.
Sustainable buildings use passive solar and cooling strategies to maximize the amount of harvested energy onsite. This typically starts with fenestration, or windows. More daylight means less reliance on artificial light or electricity.
However, there is a caveat. The building’s design must strike a balance between daylight harvesting and the right amount of fenestration. A well-insulated wall offers far better thermal performance than triple-glazed windows. Our data shows that, for office buildings, the optimum window-to-wall ratio should be between 30% and 40%. For schools it is even less: around 25%.
10 Stack Street, a new lab/office building designed by SMMA, maximizes efficiency with an advanced lighting system and daylight sensors to reduce reliance on artificial light.
The sensor-based system gauges the level of natural daylight in different parts of the building and dims the lighting when needed. Careful placement of these sensors helps to maximize energy gains in the west, south, and east-facing parts of the building.
Although not NZE, 10 Stack Street outperforms Boston’s stretch code for lighting by 30%. It serves as an example for net zero projects in terms of energy efficiency.
Occupancy sensors are another system worth considering. These work by dimming or switching off lights when a space is not in use. Similarly, plug load controls have become a popular solution for occupant behavior management, due in part to code requirements.
