What makes a sustainable building?

When you think of a sustainable building, what pops into your mind first? Solar panels? Green walls? Energy-saving mechanisms?

If that’s the case, you’re not alone. That’s how sustainable buildings are often imagined. But in reality, there can be so much more to them.

Firstly, let’s cover a few misconceptions:

1. Solar panels aren’t the only thing that makes a building sustainable.
2. Urban gardens are undoubtedly beneficial to our communities but we shouldn’t just be planting any trees and plants. It can be better to plant native and biodiverse plants.
3. A building designed with some sustainable principles such as energy-saving mechanisms here and there isn’t all that sustainable unless it is built to be integrated into the ecosystem around it. After all, a new building is entering a pre-existing environment and should strive to benefit it, not disrupt it.

When we think about truly sustainable buildings, we should also think about regenerative buildings. Regenerative sustainability is an extension of sustainability and strives to restore and revitalize nature instead of preserving it.

Naturally, a building can be ‘sustainable’ and not ‘regenerative’. This would require fewer characteristics than what is seen on the right but more than what is seen on the left. But we believe that regenerative sustainability is a significant upgrade on classic sustainability.

So, based on research from experts in the field, here are some characteristics of what an ideal sustainable (or you could say, regenerative) building looks like:

Skylights

For a building to be connected to the environment around it, it should make use of environmental agents for heating, cooling, and ventilation. Adjustable skylights provide abundant natural light, allow for ventilation and thus healthier indoor air quality and enhanced energy efficiency. In the cooler months, they can also be used as a natural heating method by capturing and retaining the sun’s warmth.

On-site renewable energy generation and storage

In many cases, “100% renewable energy” is a claim used by companies to describe the purchase of renewable energy certificates (RECs). Similar to carbon offsetting where carbon credits are purchased by companies in place of carbon emissions being reduced, this is a little misleading. Studies have shown that RECs may not be delivering the claimed environmental benefits.

A sure-fire way a building, company, or any entity can claim they are powered by 100% renewable energy is through on-site renewable energy generation. In any other case, energy sourced from the power grid can’t be guaranteed to be fully renewable, unless the grid is coming from renewable sources only. Typically, energy from the grid comes from a mix of sources like coal and solar.

On-site renewable energy generation doesn’t have to be just solar, it can also be wind, geothermal, hydropower, or another. The energy generated can be used by the building, stored for future use, or provided to the utility grid.

Native, biodiverse plants

Green roofs and vertical gardens can alleviate extreme city heat by harnessing the cooling power of plants and acting as natural air conditioners. This is becoming increasingly important as metropolitan areas are experiencing more and more extreme heat, which disproportionately affects older adults, low-income communities, and people of color (at least in the U.S.). During heavy rainfall, urban gardens reduce flood risk and water runoff. Plus, green roofs decrease air pollution, promote the mental health of communities, and reduce noise.

While non-native plants can be beneficial to ecosystems today, there needs to be more careful consideration of the diverse selection of plants in urban gardens. Native plants are easier to grow and need less water, fertilizer, and pesticides. They’ve also been said to attract a wider range of insects, setting the foundation for an ecosystem pyramid. However, in urban and other unnatural areas, certain non-invasive introduced species can contribute to a stable, biodiverse area when planted in combination with native plants. More focus should be placed on the right mix, as well as – when appropriate – consulting local Indigenous people who have extensive knowledge of the land (Indigenous people steward about 80% of the world’s biodiversity).

Seasonal shading

Being able to control the amount of sun entering a building is an important part of energy- and resource-efficient building design. External window shading can reduce the heat of a building in warm, sunny climates while saving energy and costs.

Similar to skylights, sun-control and shading devices are a form of maximizing environmental agents for heating, cooling, and ventilation. While skylights provide passive solar heating and daylighting, shading prevents unwanted solar heat gain.

Seasonal shading can come in the form of natural landscaping like trees and plants surrounding a building but it can also come from exterior elements such as awnings or overhangs, reflectors, or interior elements like blinds.

Local, natural, & recycled materials

Using certain materials like timber and hempcrete can be one form of carbon capture. Locally sourced materials support the surrounding economy and community, while reducing the amount of transportation needed.

Recycled materials make use of what’s already on the planet and it’s a sustainable alternative to traditional building materials which contribute to environmental pollution and natural resource depletion. About 50% of the raw materials extracted in Europe each year end up in buildings and roads, and construction and renovation sites alone generate over a third (35%) of the waste that sits in Europe’s landfills.

Treated and recirculated greywater

Greywater recycling is a sustainable management practice that involves the collection, treatment, and reuse of wastewater. Treated greywater can be used for flushing toilets, fire protection, green roofs and walls, non-food irrigation, and more. In a typical household, greywater constitutes 50-80% of daily wastewater, and reusing it may lead to increased resilience and adaptability of local water systems.

Captured and recirculated rainwater

A good water supply is essential in cooling air during extreme heat. But water conservation is important! Luckily, we’re blessed with nature’s rainwater which can be collected and stored for reuse, like for flushing toilets, cleaning, and other non-potable purposes. Rainwater harvesting can also reduce urban flood risks and help tackle soil erosion.

Purposeful tenants

What’s a sustainable building if it’s utilized by fossil fuel tenants? Or a company making things in single-use plastic containers? There’s one word for that and it’s greenwashing. It’s counterproductive if the work that’s being done inside is to perpetuate harm to the environment. Especially in a regenerative building, where the focus is to have a net-positive impact on the environment, it’s key that the tenants inside also engage in sustainable practices outside of the scope of the building design.

Compost

Over a third (40%) of food is wasted globally. Composting can be fairly easy with the right tools and creates a circular economy within the building where nutrient-rich soil can be thrown in the garden instead of the landfill. It’s a form of resource replenishment, where food that would otherwise be wasted is instead turned into something that will benefit the environment.

Groundwater replenished for irrigation

Not only can collected rainwater be used for a building’s non-potable uses but it can also be used for watering gardens. Rainwater is even more beneficial for gardens than tap water for many reasons such as higher nitrogen and oxygen levels. So not only is it better for the plants and nature surrounding a building but it also conserves potable water and makes use of a continuously available resource.

Garden space or organic farming

Regenerative buildings aim beyond energy efficiency. They give back to the environment and one way this could be achieved is through a community garden space or organic farm, which could benefit a building as well (depending on its purpose). Onsite urban agriculture could partly provide produce for the building or communities in the area. Garden spaces on the other hand could create an ecosystem opportunity to replenish missing local species.

Building was built around site’s ecosystem

When a building is constructed, it enters a pre-existing environment. To create as little of an impact on the ecosystem present, a building should imitate the natural processes around it and take advantage of the natural resources available (rain, wind, sun), without harming the environment and instead benefiting it.

Perhaps the most far-reaching characteristic of a building that strives to be the most sustainable it can be is biomimicry: mimicking the strategies and processes used by living organisms. It takes inspiration from nature’s solutions and translates these principles into human engineering. Rather than being a separate entity from the natural world, a regenerative building would work in harmony with its natural environment and see itself as an extension of it.

And, aside from all of this, don’t forget that the most sustainable building is the one that’s already built.