Climate Impact December 28, 2022

This old house: Rethinking the retrofit

Photo of a historic home's existing condition and a rendering of energy-efficient, water-wise, healthy retrofit strategies

A team of Georgia Tech graduate students imagines a more sustainable tomorrow for an underserved Atlanta neighborhood.

At first glance, the house doesn’t look special: Its big front porch is sagging, the paint is peeling, and its windows are boarded up. It was built a century ago and, like many other homes in Atlanta’s English Avenue neighborhood, it has been abandoned for years. 

But when a group of Georgia Tech graduate students saw it, they envisioned what it could be: an exemplar to show neighbors in the community, many of whom are burdened with high housing costs and soaring utility bills, practical ways to save money and build wealth through retrofits focused on energy efficiency, health, and water conservation. As participants in the Solar Decathlon Design Challenge, the students wanted to design an affordable, replicable model to bring vacant and derelict houses in this underserved Atlanta neighborhood into the 21st Century.  

Recognizing potential

The English Avenue area is only half a mile from the Georgia Tech campus, but it has been plagued by depopulation, crime, and violence over the past few decades. The majority of its residents are housing burdened, meaning they spend 30% or more of their income on housing. Rand Zalzala, one of the graduate students on the Solar Decathlon team, had become acquainted with residents over the course of a previous architecture class, and she and her teammates saw tremendous potential there. “We tried to find a house that’s typical of the neighborhood and figure out the best way to work on it,” she says. “Our goal wasn’t to just retrofit one house; we wanted to leave a bigger impact.”  

After they chose the project house, the team of 12 graduate students, advised by Dr. Tarek Rakha, set out to apply their skills in architecture, industrial engineering, real estate, and high-performance buildings to create strategies that would be affordable, healthy, and sustainable while also honoring the home’s historic character. To ensure the design would achieve optimal efficiency, they used Design Space Construction, a theoretical and technical framework introduced to them in a previous course.  

"The workflows we have developed in our labs is being taught in major universities and were used to win the biggest national competition of the year. I could not be more proud of Energy and Process Lab!"
John Haymaker (1967-2022), former Georgia Tech faculty member and Perkins&Will Director of Research
Designing and testing affordable solutions

From November 2021 to April 2022, they modeled thousands of scenarios involving solar panels, insulation, and other energy-saving strategies. Their hard work paid off: The final design is net positive, meaning—if realized—the retrofitted home would produce more energy than it consumed. To further reduce utility bills, the students designed a system for capturing greywater and rainwater and reusing the water for toilets and irrigation. They estimated the improvements would reduce utility costs by 72%. 

Such a dramatic reduction was impressive, but the team needed to ensure the retrofits would be affordable up front. After all, residents wouldn’t benefit from the recommended updates if they couldn’t afford to install them. Team member Peter Choquette worked with a local nonprofit organization, the Westside Future Fund, to develop a financial model that would offer subsidies and low-interest loans to offset the initial expense. 

At times, the team struggled to strike a balance between preserving the home’s original appearance and optimizing energy efficiency. “I really wanted to make sure the design respected the history of this neighborhood,” Zalzala says, adding that she resisted other team members’ recommendation to install large windows across the home’s entire south side. “I’m glad I pushed back because our design updates the house, but it’s still consistent with other homes in the area.” 

At the students’ request, a group of Perkins&Will architects, designers, and researchers served as their industry partners, reviewing and critiquing the students’ work during five sessions in March and April 2022. “We were astounded,” says Tyrone Marshall, who participated in the review sessions along with colleagues Marcelo Bernal, Roya Rezaee, Victor Okhoya, Cheney Chen, and the late John Haymaker. “Their hard work and attention to detail was evident from the very beginning, and it was no surprise they won.” 

Looking to the future

Following their victory at the Solar Decathlon competition in Golden, Colorado, in the summer of 2022, the team hoped to put their plan into action by retrofitting the subject house. It was unavailable for purchase, but the Westside Future Fund stepped up and procured a different house and the team is already designing a modified set of plans. Assuming they can raise the necessary funds, they hope to start modifying the home in 2023, transforming it into a replicable model for the community and the nation. 

As for Zalzala, she has since earned her master’s degree in architecture and started her professional life as a designer in Perkins&Will’s Boston studio. She is grateful for the relationships she built over the course of the contest, and she is helping Georgia Tech students from afar as they incorporate concepts from the first project into the new design.  

She feels it’s important to give back, particularly since the competition provided real-world experience toward her goal of combining research with design to create climate-responsive buildings. “Bringing theories and hypotheticals to life with a project like this was very helpful,” she says. “I think everyone should do something like it at some point.”