In informal settlements where houses are built without considering atmospheric factors, and people have no means of regulating the extreme heat within, there are attempts to provide sustainable heat-proof solutions.
One hot summer day, Vivek Gilani noticed his house-help looking exhausted and struggling to complete the chores. The reason, he learnt, was that she hadn’t been sleeping well at night. During the day her house in an informal settlement in Mumbai got so hot that it felt like being in an oven at night. The heat couldn’t be abated with just a ceiling fan.
Gilani, who runs cBalance – a company that provides solutions to mitigate ecological footprint – wondered if thermal comfort could be provided to homes in informal settlements. Could these heat-proof solutions be made easy to install, as well as be sustainable?
The company came up with solutions involving heat barriers to be fitted either over or under the roof.
They decided on the materials based on a few factors such as the materials’ properties and life.
Partnering with Hasiru Dala – a Bengaluru-based organisation working with waste pickers – cBalance identified Bengaluru’s Jyothipura slum for the pilot project.
With Hasiru Dala’s help, the team surveyed the houses in Jyothipura, recording details such as number of windows.
They spoke to the residents to understand how those who spent the entire day in the house felt, in which seasons they felt comfortable staying in the house, and the impact of heat on their work and health.
“We didn’t want a top-down approach. So we ensured community participation,” Anusha Mohan, project associate at cBalance told Village Square.
Thirty houses were shortlisted.
These are single-storeyed brick houses with asbestos cement sheets serving as the roof. About 90% of the houses are self-designed and do not take ventilation, shading and circulation into account, according to Mohan.
The team presented to the residents six working solutions that are in use in Pune. Of the 30 shortlisted houses, based on the residents’ willingness and the houses’ feasibility to install the solutions, ten houses were chosen for the pilot programme.
Based on details such as orientation and age of the houses, residents’ feedback on design, material and mechanism, and taking the vernacular ways used to combat heat into consideration, the team decided to try four of the solutions in Jyothipura.
“After deciding on which house received what solution, we got the residents’ agreement before installing the solution,” said Mohan.
The team installed over-the-roof solution in some houses and under-the-roof solution in others, after taking factors such as structural stability and construction material into consideration.
The over-the-roof solution had three models.
Using water-filled PET (polyethylene terephthalate) bottles was the simplest of the solutions. “Because water can absorb the heat and stabilise the temperature on the roof,” said Mohan.
Ecoboard roofing sheets made of multi-layered plastic waste, with good insulation properties, were used in some houses.
Cross-linked polyethylene foam – also known as XLPE – sheets were used in some.
Some of the over-the-roof solutions are dynamic – they can be opened and closed to enable air exchange.
For under-the-roof solution wood wool panels made of wood chips, cement and water were used.
PET bottles and wood wool panels are the static solutions since they cannot be opened for air movement.
“All of them are sustainable and eco-positive solutions that don’t generate any waste,” said Mohan.
The cost of a solution ranges between Rs 5,000 and Rs 30,000.
Prior to installing the heat-proof solutions, the temperature and humidity inside the houses were measured.
“The three-part agreement between cBalance, Hasiru Dala and the house owners was stipulated for a year of experimentation,” Akbar Allahbakash, who heads the Hasiru Mane project of Hasiru Dala, told Village Square.
For a year cBalance maintains and monitors the performance of these solutions through all the seasons.
“After the first year, it is up to the owners to continue or discontinue using the solution,” said Allahbakash.
After the installation, the team discussed with the residents about their pre-and-post installation experience.
The residents’ responses about the solutions have been mixed.
“When there was no electricity from 3-5 pm, everyone came out of their houses because of the heat. But our family stayed in because we didn’t feel the heat inside the house,” said Selvi, whose house has the eco-board solution.
Muttamma, whose house has the internal or under-the-roof wood wool panels, said she would prefer the external solution.
“I accepted the solution because you (cBalance and Hasiru Dala) came and asked. But it’s very hot inside the house even at 9 am. Before installing the solution, we could at least stay inside the house. But now we can’t,” said Muttamma. “During the rains, it was good. But in summer, it’s hot. The electricity bill has gone up significantly.”
Though there has been a mixed response, the feedback and the observations have been illuminating for the team.
Dynamic solutions that can be opened and closed to enable air exchange appear to be more effective than static solutions.
Changes in annual, seasonal climate patterns, temperature and humidity and the heat changes throughout the day influence the level of comfort.
Stray cats that abound in Jyothipura scratched and damaged the boards.
Some felt that materials that are good insulators may be harmful, as wood wool panels caused skin rashes.
After observing the performance of the solutions by measuring temperature and humidity throughout the year, and based on users’ feedback, the team plans to make the solutions more effective.
cBalance’s vision then is to train members of women self-help groups to install these solutions and enable them to turn entrepreneurs.
Also, cBalance plans to discuss with the Slum Development Board and the Pradhan Mantri Awas Yojana that deal with public housing, to install these solutions in upcoming allotments and existing housing.
“We’d like to bring in stakeholders and arrive at a policy to build climate-proof houses,” said Allahbakash. “Because most of the conversations around climate change are focused on the macro and leaves out the micro. The mitigation and adaptation strategies are not focussed at the community or household level.”
At this stage, a comprehensive, one-size-fits-all solution looks far-fetched. “We might get different results for these solutions in, say, Chennai or Mumbai which are more humid,” said Allahbakash.
As one of the winners of Ashden’s Fair Cooling Fund, cBalanace tries to arrive at effective solutions.
The lead image at the top of this page shows one of the heat-proof solutions in Jyothipura slum near Bengaluru (Photo courtesy cBalance)
Vijayalakshmi Sridhar is a Chennai-based writer of fiction and features.
