Earlier this year, the Modernist mansion overlooking Biscayne Bay, which was sold as the only solar-powered home on Miami Beach, sold for $ 15.25 million. According to some estimates, 112 solar panels on the roof are sufficient to operate an entire 5,500-square-foot building for weeks or months.
Does that mean the house is green? As with many, the definition is important. Building a house (processes such as concrete injection, marble import, steel forging, etc.) requires enormous energy. When that energy is generated, a large amount of CO2 is released into the atmosphere, exacerbating the “greenhouse gas effect” that causes climate change. In fact, buildings account for about 40 percent of the world’s greenhouse gas emissions. And much of it comes from the energy used to build buildings in the first place, not from operating energy (the power to power lighting and air conditioning). It is known as embodied energy.
“It’s undeniable that a house of this size and complexity contains a lot of embodied energy,” says Max Strang, the architect who designed the Miami Beach dwelling. He hopes that solar panels will generate enough surplus energy over time to pay off some of their debt. “Not trying to offset the embodied energy is just sitting vaguely,” Strang says.
However, the repayment can take over 100 years. Today, Strang and his colleagues are working on the reality that there is no such time in the world. “If we want to maintain the Paris Agreement’s goal of warming to or near 1.5 degrees Celsius, we need to deal with embodied energy right now,” says Vancouver architect Michael Green.
So when Green refurbished a 1912 artisan-style home in North Vancouver for a couple with grown-up children, he did whatever he could to minimize the energy consumed. “The first green thing we did was not to destroy the house. Reusing what we have is a big part of sustainability,” he says. And when I made the back of the house bigger, I chose wood as the main structural material. Unlike steel and concrete, wood is made “using the power of the sun,” he says. “I want to use photosynthesis over solar power,” he adds. This means that reducing the energy currently embodied by choosing wood is better than trying to produce more energy in the future. (Especially because manufacturing PV panels requires a lot of energy.)
LEED, the leading “green” building certification system, has little emphasis on embodied energy. That’s why architects are looking to apps like Tally (from Philadelphia’s architectural firm Kieran Timberlake) to sum up the energy that goes into a building. Even with the app, it is not easy to calculate the embodied energy of a building. But common sense is very helpful. The less you build and the less concrete and steel you use, the better. And the less transportation you have to do, the better. Thomas Bercy and Calvin Chen of Austin Architects BERCYCHEN STUDIO tend to use stone instead of concrete whenever possible. It does not require energy for production and works with a local quarry, so there is very little energy to transport to the construction site. When designing a private home on Whidbey Island, a suburb of Seattle, local architect Miller Hull used recycled materials wherever possible (some from another home in the client’s family).
Of course, operational energy remains important. Bercy Chen’s homes often have rooftop solar water heaters (basically sun-exposed glass top tanks) that are affordable and virtually universally available, along with other energy-saving systems. House Zero, where Snohetta experimentally converted the Harvard building into a laboratory for energy use research, uses a glass “solar chimney” to ventilate the basement. Returning to Whidbey Island, Miller Hull placed a solar array on a meadow not far from his home. “Take-away means that you can have an energy-efficient home,” says Chris Hellstan, director of sustainability at the company.
Some architects go a step further and adhere to a set of guidelines to minimize the need for operational energy in their homes. So-called passive houses rely on natural phenomena (sunlight, sunshades, ventilation) rather than active heating, cooling and lighting. Lots of insulation and triple-glazed windows keep the heat indoors in winter and outdoors in summer. Perkins & Will’s SoLo House, an alpine prototype in Sou Valley, north of Whistler, British Columbia, follows some of these principles in large windows strategically placed and sized to maximize solar gain. Nevertheless, it meets the Passive House Institute’s PHI low energy building standards. It promotes cross-ventilation when closed and ventilation when open.
Almost all types of dwellings can be passive houses. In Brooklyn, GRT Architects is renovating a Greek Revival-style home from the 1840s. When completed to the standards of a passive house, it requires only 10% of the energy of a traditional house. One of the challenges is that the insulation needed occupies a lot of space, but GRT co-founder Tal Schori said: For homeowners who don’t want to reinvent the wheel, a California company called Plant Prefab offers passive houses built in a variety of factories.
There are some positive signs about embodied energy issues. In just two years, the Carbon Leadership Forum, an organization where architects and engineers are looking for ways to reduce building energy, has grown from less than 400 to more than 6,500. And local branches are springing up all over the country. “The architects have finally recognized the urgency and have taken action,” said Kate Simonen, the founder of the forum. -Fred A. Bernstein
Originally appeared Architectural digest