In Piayu Village in Batam’s Sei Beduk subdistrict, many families live in homes with metal roofs and cement-sheet materials that absorb and retain heat. Rapid urban development has reduced green space that once helped moderate local temperatures, while air conditioning remains beyond the reach of many households.

Evidence generation

Arwin Soelaksono, Program Director of Habitat for Humanity Indonesia, says the project is designed to generate evidence that can improve housing solutions for low-income communities. “We are testing which cooling measures work best, what they cost and whether families are willing to adopt them. The findings will help us design more effective and affordable homes for communities facing rising temperatures.”

According to Jim Kendall, a consultant supporting the project, Batam’s relatively stable climate makes it an ideal research setting because interventions can be tested under comparable conditions throughout the year. Kendall, an architect, was formerly Manager of Construction and Appropriate Technology with the Housing Support Services Unit under Habitat for Humanity’s Asia-Pacific Programs Department. He led design of the project with Karnen Dasen, Program Development Manager, and worked with Rudi Nadapdap, Senior Manager of Field Operations, both from Habitat Indonesia, to provide technical support in the project’s implementation.

Many studies focus on individual cooling measures in isolation, while Batam’s project compares multiple interventions side by side, helping identify which approaches deliver the greatest benefit for families.

While many studies measure air temperature and humidity, this research is using Wet Bulb Globe Temperature (WBGT) Meters to measure heat stress, a more accurate measure of what the human body actually feels by including radiant heat that significantly influences how hot a home feels to its occupants, particularly in low-cost housing.

Results to date

By mid-September 2026, all 10 new climate-responsive homes had been completed, and 30 existing homes had been retrofitted using five passive cooling approaches, including roof ventilators, solar-reflective paint, reflective roof insulation and ceilings, rooftop gardens and external roof shading systems. The remaining retrofits of the 10 control group homes will be completed shortly.

Several phases of thermal performance testing were conducted. These included baseline testing to see the performance before any improvements, and testing of singular and combined retrofits to explore the increased benefit of combining separate interventions. For example, some households that installed roof ventilators also applied solar-reflective paint or other variations. Performance testing was completed on October 1, and the data is currently being analyzed to identify the findings of this research.

“We’re looking at three key factors: cost-effectiveness, thermal performance and cultural acceptability,” says Kendall. “Understanding that balance is essential if these solutions are to be scaled.”

The lessons emerging from Batam will help inform future climate-responsive housing designs across Indonesia and other Habitat entities operating in similar climates. Habitat Indonesia plans to combine findings from Batam with earlier passive cooling research on Java Island to identify the most effective approaches for different communities.

Adapting to changing climate

For Soelaksono, the importance of the work extends beyond comfort. Extreme heat can worsen health risks, reduce productivity and diminish quality of life, particularly for families already facing economic hardship.

“Passive cooling offers an affordable way for communities to adapt to a changing climate. We hope this research can help make housing improvements more sustainable and accessible for those who need them most,” he says.

Since 1997, Habitat for Humanity Indonesia has been working with families to build or improve a place they call home. Through multisector partnerships, Habitat builds resilient homes with communities, strengthens policies and inspires action for housing. Learn more at habitatindonesia.org

The couple first partnered with Habitat for Humanity Indonesia in 2005 to build their own home. They were among 10 families who contributed their labor to building each other’s homes under a now defunct program known as “Save and Build.” Each family also repaid a 9 million rupiah (over US$500) mortgage loan within two to three years. 

Compared to when they first moved in almost 20 years ago, their original two-room home is now bigger and more comfortable. Hendro has increased living space by constructing three more rooms as well as building an additional toilet and a store room. He continues to work in the construction sector while Erta runs a home-based business that sells groceries as well as gas canisters for household cooking.

Foundation for education

Their eldest son Santo is now 25 years old and works as a construction supervisor with Habitat for Humanity Indonesia because of his interest in addressing the intense heat on Batam. The opening came via a job ad on LinkedIn for a construction supervisor for Habitat Indonesia’s work in passive cooling design. “The temperature can rise to 40 degrees Celsius. If a metallic roof is used, it makes the house very hot and uncomfortable for people. I want families to have a better life,” Santo says.

He adds, “I love construction. I’ve been making things such as chicken cages made of wood since I was young. I used to follow my father to the construction site. Perhaps I was influenced by him.”

He went on to study architecture at the Duta Wacana Christian University in Yogyakarta. His thesis on building a dive resort with bamboo in a coastal area in Batam was highly rated by his professor, according to Santo. His professor had recommended him for a Masters degree course in architecture but he decided not to pursue it. “Working for the community is better as I can see the impact,” Santo says. His mother Erta quips, “He knows his place well.”

Santo’s younger brother, 22, is studying power plant engineering while his sister, 19, is awaiting admission to a university after graduating from high school. 

Since 1997, Habitat for Humanity Indonesia has been working with families like Hendro and Erta to build or improve a place they call home. Through multisector partnerships, Habitat builds resilient homes with communities, strengthens policies and inspires action for housing. Learn more at habitatindonesia.org

Now she employs four workers from the community. They wash, dry, peel and cut the cassava that Tasnih’s husband buys from the market each day. Due to the long fermentation process, she starts at 9 a.m. and ends at midnight. She says, “Patience is key.”

Surprisingly — or not — the kitchen is her favorite part of her home. “I’m proud of my products. Whenever I get bulk orders, I would take photos and post online.”

Tasnih is also among families who are partnering with Habitat Indonesia under its innovative passive cooling project on Batam. In February 2026, reflective roof paint was applied to her home. “The floor felt cool at dawn. It feels like we have A/C,” she says. Two months later, in April 2026, a rooftop ventilator was installed at the highest point of her home as a second phase intervention to manage heat. 

At home, personal touches such as a framed wedding photo can be seen. A few drawings of her eight-year-old daughter Karos Malasari are on the walls as well as their bedroom’s door. While her daughter likes to draw, her ambition lies elsewhere. “I want to be a football player,” says Karos Malasari who came home from playing football with children from the village.

Since 1997, Habitat for Humanity Indonesia has been working with families like Tasnih to build or improve a place they call home. Through multisector partnerships, Habitat builds resilient homes with communities, strengthens policies and inspires action for housing. Learn more at habitatindonesia.org

In Kampung Sukadamai (“Village of Peace” in Indonesian), Kartina and her husband Muhaeni are among the first few families who opted for a passive cooling design that is in line with their interest. “When I learned about rooftop gardening, my passion came out,” said Muhaeni, who worked as a gardener for a few years in late 1990s. Given the local community’s love for gardening, their village is informally known as Kampung Sayur, or Village of Vegetables.

Tending to the rooftop garden is now part of Kartina’s daily routine. She wakes up early to help her husband prepare egg-based snacks and iced coconut drinks for his motorcycle cart. Then the couple will climb a ladder by the wall of their home to go up to their rooftop garden. For about two hours, they will water and tend to their 140 pots of tomato, eggplant, spinach, eggplant and celery. When the vegetables are ready for harvesting, they plan to sell the additional crops after keeping some for their own consumption.

Design features

According to Santo, a construction supervisor with Habitat Indonesia, the design of the rooftop garden provides a two-layer insulation against external heat. The soil of the planters provides thermal mass which absorbs the sun’s radiant heat and dissipates it slowly, and the planters rest on a metallic structure built above a sloped zinc roof, which then eliminates the heat conducting down to the living space below. Additionally, evapotranspiration by the plants and soil produces a natural cooling action, lowering local air and surface temperatures.

Kartina and her husband Muhaeni built a new home in 2023 under a partnership between Habitat Indonesia and Habitat Singapore. Before they partnered with Habitat, they were living in a house made of wood that made one feel warm just staying indoors. Muhaeni said. “Previously, we had to use a standing fan and turn on the ceiling fan daily. Now, not every day.”

A village leader for 12 years, Muhaeni said he knows all the 450 families in Kampung Sukadamai. Two years after moving into their new home, he built a veranda with a tiled floor. That’s where he, his wife and their son Mohamad Wahid could relax, chat and have snacks.

Since 1997, Habitat for Humanity Indonesia has been working with families like Tasnih to build or improve a place they call home. Through multisector partnerships, Habitat builds resilient homes with communities, strengthens policies and inspires action for housing. Learn more at habitatindonesia.org

Ways of supporting Habitat
In Hong Kong, one could help to improve living conditions in public housing or subdivided units. “Hong Kong is a very wealthy city. At the same time, the income disparity is huge. Often, people look at Hong Kong and see all the wonderful roads, public transport, people can move around easily, everything works. People don’t realize that within the city, there are still people living in poverty and in less-than-optimal housing units. Building that awareness and educating people is so important. Then we offer opportunities for individuals to work within a community.” 

Acknowledging that people are busy, Olivia thinks it’s possible to go out and work in a community. “I think people can always squeeze out a few hours on a weekend because once you step out of your own comfort zone into a community that we don’t normally see, it brings a very different perspective.”

Olivia is also thinking about how to get the next generation excited about Habitat’s work. Whether it’s Generation Z or Generation Alpha, every generation is different. “How do we have those conversations with them so they understand how they can actually make a difference and not feel defeated?”

When it comes to advocating, one doesn’t have to be an industry leader. Olivia says, “Even if you are a young person in school, in the universities, you can advocate for the work that Habitat is doing, within the student union, within the network that you’re in. For those of us who are in the corporate space, we advocate when we have an opportunity with our colleagues or when we are sitting on panels, talking about social impact.”

Natural born storyteller
Olivia puts her storytelling skills to good use when furthering the cause of Habitat. While she remembers each family with whom she has built alongside, there are some families who left an indelible impression. One of them was a family on Batam island, Indonesia, that she helped to raise funds for home construction through a half-marathon fundraiser. As she was living and working in Singapore — about an hour’s ride by ferry from Batam — she worked on a build in early 2006 on Batam as part of an all-women volunteer team. 

When Olivia returned to Batam a few weeks later, to build in another village, she was invited to the new home of the homeowner whom she met during her previous build. The homeowner said, “We don’t have much and I don’t have a gift for you. The only gift I can give you is this glass of water. I just wanted to tell you how much I really appreciate you and your friends. I cannot believe that 12 women managed to finish my floor so that we can move in and have a safe home.”

Another memorable story came from the 2011 Cambodia Big Build in a village in Oudong, Kandal province, about 40 kilometers from the capital of Phnom Penh. By the end of the weeklong build, Olivia and her fellow volunteers had finished nearly all the work including the roof. As soon as the ribbon was cut and the home dedication ceremony was over, the homeowner family moved in. The volunteers who worked alongside the family were invited to come into the house, sit on the floor, share stories. But first, they had to take off their shoes. “Because now we’re stepping into her home. For me, that’s really powerful — to watch the family being able to move in on the spot and the homeowner making sure that we’re treating her home with respect.”

A privilege to serve
As a long-time volunteer and supporter, she considers it a privilege to contribute as a board member. “Habitat for Humanity Hong Kong’s board was the first board that I had ever sat on. It helped me to understand the role of board versus management and how the board is there to support the organization through the contribution of expertise, time, and resources.

She adds, “While on Habitat for Humanity International’s board, I have gained a better understanding of how a very reputable nonprofit is able to raise the amount of resources and do the work that they do. It is comparable to any large commercial for-profit organizations in home building, for example.”

When she joined Habitat for Humanity International’s board of directors in March 2020, she asked herself, “What can I bring to the table? The other board members are industry leaders and top of their field.” Having served on both the Hong Kong and international boards, she said, “They are just amazing. All of us have passion for the work that Habitat is doing and I think that makes it easier.” Being in different time zones can be challenging when it comes to staying up late or getting up early for virtual meetings with Habitat’s international board. It helps that Olivia is known both as an early bird and a night owl among the international board members.

So much more to do
Whichever hat she’s wearing, Olivia has seen how Habitat’s work is increasingly complex. As a volunteer, she recalled using thick heavy bricks that served to insulate households during the harsh winter in Mongolia (where Habitat used to operate). As a member of Habitat for Humanity International’s board, she is better informed about the ways that Habitat incorporates energy efficiency through solar panels in Asia to energy-efficient homes in the United States and Europe. “Even before those buzz words came about, I think Habitat has been looking at building homes that are not only climate-resilient but also energy-efficient. Now, with the technology, we’re able to make sure that we do a lot more of that.”

When asked if Habitat is closer to realizing its bold vision of a world where everyone has a decent place to live, Olivia considers herself to be an eternal optimist. That said, the reality is there are still 838 million people who lived in extreme poverty in 2025, surviving on less than US$3 per day (World Bank, 2025). Low-income families are also disproportionately affected by the global housing crisis. At the end of 2025, 117.8 million people worldwide were forcibly displaced from their homes, according to the UN Refugee Agency. Olivia concludes, “We’ve definitely come a long way. On the other hand, in the volatile world that we live in, we still have so much more work to do.”

In the midst of uncertainties, Olivia says, “We cannot afford to lose hope that we can make a difference. If we allow that to happen, then we stop doing what’s right. We may also start to be indifferent to injustice thinking ‘I should just look after myself, my family and my friends.” She adds, “We need to make sure that we can open the door to hope, kindness and empathy.”

Her passion for Habitat is also rooted in her faith. “I love Habitat and I love working with Habitat. We demonstrate Christ’s love through our actions. If you think about the builds that we do around the world, I would say our common language is love. I’m here because I love you. You’re my neighbor. I think that’s the beauty of the work that we do in Habitat.”

Sophal says, “Because we were poor, we faced discrimination. We had to take a microfinance loan of US$3,000 that we’re still repaying today.”

She makes a living by selling lotus flowers from her small stall at the foot of Oudong mountain in Kandal province. It has been her source of livelihood even during the 2018 Legacy Build when 64 international volunteers built alongside Sophal’s family and others.

Her home is just a short ride away on her motorbicycle. Sophal has kept her home neat and tidy with a small garden. She says, “I feel I can better cope with the hardships in life now that we have a secure home.”

Two of her adult children are working at a nearby garment factory, contributing to the total household income of US$250 per month. Sophal plans to completely repay the microfinance loan in the next two years.

With their savings, her family could build an extension so Sophal’s eldest daughter and her family could live next door. They can also afford to spend money on home maintenance.

“Having a home of my own marked the biggest change in my life. I will focus on earning money so as to support my nine-year-old granddaughter’s education. I hope she can complete her studies to improve her future prospects.”

Eight years after moving in, Sophal said her family is friendly with other families who are also Habitat homeowners. She shares, “We feel a sense of belonging in this community.”

Since 2003, Habitat for Humanity Cambodia has been working with families like Sophal to build or improve a place they call home. Through multisector partnerships, Habitat builds resilient homes with communities, act as a voice for policy changes and implements programs to make housing markets more inclusive. Learn more. https://habitatcambodia.org/en/