Due to poor and outdated housing infrastructure and lack of material resources, lower-income individuals are less prepared than those with higher incomes to weather the coming climate crisis — in particular, the increasing risk of heat-related death and illness from longer and hotter summers and more severe heat waves.

But with support from the National Science Foundation (NSF), researchers at the University of Notre Dame — including Ming Hu, associate professor of architecture; Chaoli Wang, professor of computer science and engineering; Matthew Sisk, associate professor of the practice of data science; and Eugenio Acosta, senior associate director of the Fitzgerald Institute for Real Estate — are using data and analytics to lower energy costs and improve living conditions for those living in older, less efficient homes, starting in South Bend.

Led by Hu, also the dean for research, scholarship and creative work within the School of Architecture, the BUILT2AFFORD initiative is pairing advanced computational technology and strong community partnerships. The goal is to develop, test and validate a tool that uses machine learning and Google Street View to identify housing units suitable for low-cost passive retrofits — things such as improved insulation and air sealing, new windows, upgraded ventilation systems and exterior shading.

The group, which also includes faculty from the Center for Broader Impacts, is partnering with the city of South Bend, the Near Northwest Neighborhood (NNN), South Bend Heritage Foundation and Oldtown Capital Partners to target single-family homes and apartment buildings downtown and on the city’s near northwest side, an economically diverse area with pockets of wealth but high overall levels of poverty.

In lower-income neighborhoods especially, older homes tend to suffer from inadequate insulation; leaky ducts; cracked floors, ceilings and walls; drafty doors and windows; outdated HVAC systems; and other effects of age and disrepair, leading to higher energy costs and less safe and comfortable living conditions.

“We’re all living in the same housing stock. So when there’s research to come up with low-cost solutions to what are probably going to be common issues, it’s really very important to us because, a lot of times, it seems like if you’re trying to scratch the surface of energy efficiency in your home, you’re looking at a $50,000 or $60,000 bill.”

“Generally speaking, older buildings do not have the same thermal properties as newer buildings in terms of absorbing heat and resisting heat transfer from inside to outside and vice versa,” said Hu, who also is a concurrent associate professor of civil and environmental engineering and earth sciences. “So this can create higher risks for indoor heat exposure.”

Pregnant women and children, the elderly and those with respiratory or other health issues are especially vulnerable, Hu said, as are those living in traditionally colder climates, where buildings and other infrastructure are less resilient to extreme heat.

Hu noted that people spend about 80 percent of their time indoors. For elderly people, the number is closer to 90 percent. Our homes, she said, have an outsize influence on our health.

Kathy Schuth, a Notre Dame graduate in architecture, is the executive director of the Near Northwest Neighborhood Inc. She noted that, from a structural standpoint, the neighborhood looks much the same today as it did in the 1920s.

“We’re all living in the same housing stock,” Schuth said. “So when there’s research to come up with low-cost solutions to what are probably going to be common issues, it’s really very important to us because, a lot of times, it seems like if you’re trying to scratch the surface of energy efficiency in your home, you’re looking at a $50,000 or $60,000 bill.”

A data-driven approach

Part of the NSF’s Civic Innovation Challenge, the BUILT2AFFORD project involves the creation of representative layouts for thermal comfort simulations — essentially, models of relative comfort based on a home’s size, layout, location and orientation, among other factors.

To do this, researchers partner with property owners to collect and analyze data from a variety of housing types.

Leveraging multiple computer vision models developed by the team since 2023, they begin by using Google Street View to extract the physical characteristics of housing that influence energy use and indoor thermal comfort. These data points, combined with additional housing property data from open-source databases, form the foundation of the prediction tool BUILT2AFFORD.

To ensure the tool’s accuracy and robustness, the research team conducts field audits. These audits start with the creation of a 3D scan of the relevant house or apartment unit. Next, the team members take thermal images, measure for moisture content and document building materials and insulation. Finally, they place sensors around the house to measure temperature, humidity and air quality for one week.

The resulting data are then analyzed to identify problem spots, with the goal of creating an exposure model to predict risk across housing types.

“The idea is really around, what are low-cost solutions we can use to find where the problems are, and then low-cost solutions that we can use to help address those problems?”

So far, around a dozen property owners, including South Bend Heritage Foundation and Old Town Capital Partners, which owns the Mar-Main apartment building downtown, have agreed to participate in the project.

“The idea is really around, what are low-cost solutions we can use to find where the problems are, and then low-cost solutions that we can use to help address those problems?” said Sisk, the team’s data science professor who leads the Geospatial Analysis and Learning Lab within the Lucy Institute for Data & Society. “So it’s largely about targeting resources to the proper locations.”

As a resident of the Near Northwest Neighborhood, Sisk is well aware of the challenges that come with owning and living in an older home. His house, within the Chapin Park Historic District, was built in the late 1800s, before air conditioning, foam insulation and double-pane windows, among other modern materials and conveniences.

“I run into a lot of the same sorts of issues” as other homeowners, Sisk said, “like places that are ridiculously hot for no good reason, that the AC doesn’t do anything for, and it’s basically unmanageable in the summer.”

That said, every house is unique.

Early on in their research, Hu and her team collected data from two houses of similar size, age and location — one fully renovated, including new heating and cooling systems and added insulation; the other largely untouched — with surprising results: Compared with the renovated house, the unrenovated house performed much better in terms of temperature and air quality.

Among other things, Hu said, “this just tells us that the conventional wisdom, the conventional solution of just adding insulation everywhere in the house does not necessarily work.”

Reed Lyons is among the homeowners participating in the project, having learned about it during a presentation Hu gave to NNN residents in early October.

A software developer, Lyons lives with his wife and two children in a two-story house on Cottage Grove Avenue. The house was built around 1914. The NNN, as part of its affordable housing program, acquired and renovated the property in 2012. The Lyonses bought it in 2019.

“We’ve noticed some issues with efficiency and some issues with air quality, just knowing that it’s an older home,” Lyons said. “So we’re just curious to see what the data show.”

He said working with Hu and her team — which in addition to Sisk and Wang includes Lucy Graduate Scholar Siavash Ghorbany, a doctoral candidate in civil and environmental engineering; doctoral candidate in computer science Siyuan Yao; and multiple undergraduate research assistants — has been a breeze.

“It’s really been a low investment in terms of our time and resources, and they’ve been really easy and wonderful to work with,” he said.

Notre Dame has a long relationship with the NNN, having partnered with the organization on a number of projects in the past. Notably, the Notre Dame Lead Innovation Team has worked closely with the community development organization and de facto neighborhood association to reduce lead exposure in the neighborhood, particularly among children.

“The NNN is kind of optimal for these kinds of projects,” Sisk said. “They have an extremely engaged neighborhood organization, and their president is an architect by training. They’ve been a key partner for years in many grants and many projects with us.”

For the purposes of this project, Sisk said, the neighborhood is also “very representative” of a Rust Belt neighborhood — socially and economically diverse, with brick-lined streets of well-preserved homes in Craftsman, Tudor and Victorian styles next to “some of the most historically troubled blocks in the city.”

Next steps

In collaboration with the Fitzgerald Institute for Real Estate, Hu and her team are already applying for a phase 2 NSF grant to validate their research, with plans to retrofit a certain number of homes and analyze the results. The grant would pay for at least 80 percent of the cost of the retrofits, with local programs potentially covering the rest.

The city of South Bend, in partnership with enFocus, currently pays for some energy upgrades as part of Greener Homes, a pilot program for low-income, elderly homeowners who are part of Habitat for Humanity of St. Joseph County’s Aging in Place Program. The program was established with support from the Community Foundation of St. Joseph County.

Alexandro Bazán is the director of sustainability for the city.

“The city of South Bend is looking forward to continued collaboration with Notre Dame,” Bazán said, adding, “This project is a great opportunity to advance our community’s goals on climate action.”

Using the indoor heat exposure model, Hu and her team ultimately plan to create an online tool, or dashboard, to quickly and easily identify housing units suitable for passive, low-cost energy upgrades based on design indications, energy efficiency and health risks — without the need to actually enter the homes and collect data.

“The dashboard will be tied to the indoor heat exposure model, so the indoor heat exposure predication is the key,” Hu said.

Separately, Hu is also collecting data outside of South Bend, in Chicago and elsewhere, so that once the dashboard is up, it can be adapted to other regions of the country.

“We’re also committed to a series of training workshops for policymakers, developers and residents to show them how to use the dashboard if they want to,” Hu said. “So that is continued training that is for South Bend and for Indiana in particular.”

Social responsibility

Hu’s research is incredibly timely.

According to the United Nations, by hitting the poorest hardest, climate change increases existing economic inequalities and causes more people to fall into poverty. A World Bank report estimated that an additional 68 million to 135 million people could be pushed into poverty by 2030 because of climate change.

From a public health perspective, a warming planet increases the risk of heat-related illnesses such as heat stroke — particularly among vulnerable populations such as children, pregnant women and older adults. It also worsens air quality, which can lead to asthma attacks and other respiratory issues, and it contributes to unhealthy concentrations of ground-level ozone, which can damage lung tissue, reduce lung function and inflame airways.

“When I was trained, at least at Notre Dame, we were taught a lot about the social responsibility of architecture. The building is not merely an art piece; even when it aspires to be artistic, it serves as civic art, designed with a profound responsibility to its users, rather than existing as a mere monumental sculpture."

Heat even affects sleep, the most fundamental of human needs.

But it’s not just the heat — extreme cold is a concern as well.

“We all have to realize that things are going to be way more variable moving forward,” Sisk said. “We’re going to have weeks of 95-degree summer weather, but then also sub-zero weeks during winter, and we have to be prepared for both, which is super hard.”

According to Hu, the most recent climate report for Indiana predicts average temperatures in the state will rise by 5 to 6 degrees over the next 30 years, increasing the frequency, duration and intensity of heat waves. The average hottest day of the year is projected to increase to 105 degrees.

“Our infrastructure, including our housing, is not built for excessive heat. Our energy grid is not built to accommodate higher peak load during the summertime,” Hu said. “So what we’re worried about is the domino effect. If the grid goes out, there’s no cooling in those houses. What happens if that lasts a couple of weeks? Where do people go?”

A native of China, Hu holds multiple degrees in architecture from Notre Dame and elsewhere. She has a doctorate in civil and environmental engineering from the University of Maryland.

Prior to joining the Notre Dame faculty, she spent several years in private practice, designing signature buildings for high-profile corporate clients and working on urban redevelopment projects around the globe. She also taught at Maryland as well as at Catholic University of America and the Rochester Institute of Technology.

She returned to Notre Dame, she said, out of a sense of social responsibility.

“When I was trained, at least at Notre Dame, we were taught a lot about the social responsibility of architecture. The building is not merely an art piece; even when it aspires to be artistic, it serves as civic art, designed with a profound responsibility to its users, rather than existing as a mere monumental sculpture,” Hu said. “So I always wanted to go back to social responsibility as a part of architecture, and I was always interested in how beauty actually functions. What is the experience of the occupants?”

That same philosophy — consistent with a fundamentally Catholic concern for the common good — animates the Lucy Institute as well.

“This is an ideal situation for a Lucy collaboration project, because we’re very deeply involved in the research part of it, but also in the ‘for societal good’ part,” Sisk said. “This kind of sums up those two sides of what we are designed to do.”