Students’ winning idea: Paint your roof white

VOLUNTEERS and residents of Barrio Luz started painting their roofs white on April 29. White roofs are said to reflect sunlight by 80 percent resulting to lower surface temperature that will decrease electricity consumption. Paint your roof white was the winning proposal of USC biology students in the Youth Climate Change Project. IRENE SINO CRUZ

“Paint your roof white.” This is one household solution that three students of University of San Carlos (USC) suggested to manage the effects of climate change.

“White roof can reflect sunlight more than dark-colored roof, resulting in lower surface temperature (and) lower cooling demand and, thus, reducing energy costs,” says project co-proponent and biology graduate Kimberly Lucero.

Lucero, Geraldine Cercado and Ferdinand Renfred Zapata wrote the proposal, “Painting Roofs White for a Greener Tomorrow: A Response to Climate Change,” which won top prize in the Youth Climate Change Project.

The competition sought young people’s simple household solutions against the effects of climate change. It was initiated by Silliman University in Dumaguete City, with the support of the World Bank, Smart Communications, USC in Cebu, and Central Philippine University in Iloilo.

Lucero says the idea to paint the roof white was first broached by their professor, Dr. Glen Martin Green, a research scientist in the United States who now teaches full-time at the USC biology department.

“The overall concept embraces green architecture where we ensure that our design and structure utilizes less energy,” Green says.

Green’s house in Metropolis Subdivision in Barangay Pit-os is designed using green architecture principles. Yes, its roof is painted white.

His monthly electric bill is between P650 and P1,200, which, he says, is low for a three-story house sitting on a 100-square-meter footprint.

“The white roof contributes to that because not too much light is converted into heat and gets absorbed by the house,” he explains.

Nothing new

Painting roofs white is not a new idea.

Dr. Steven Chu, US Energy Secretary and Nobel laureate in physics, advised US television audience of Comedy Central’s Daily Show to “make it (roof) white” because it reduced air-conditioning cost by at least 20 percent in hot, sunny weather based on studies by the Lawrence Berkeley National Laboratory.

Citing findings from the Florida Solar Energy Center, Lucero notes that white-colored roof reflects up to 80 percent sunlight compared to dark-colored roof, which reflects only 10-20 percent.

“Light that is not reflected becomes heat and is absorbed by the roof making your house hotter,” she explains.

A roof with lighter color has been found to have higher albedo—the amount of light reflected back into space—and absorb less radiation than one with dark color.

Less-absorbed light radiation translates to lower roof surface temperature, directly reducing heat gain. This lowers the need for more ventilation, thus cutting energy consumption.

Experiment

Lucero’s group tested its idea on April 29 at Barrio Luz in Cebu City, which has won awards for waste segregation. The barangay has 3,000 households.

The roofs of 20 houses, with a combined area of 700 square meters, were painted white on that day. (The project targeted to paint a total of 1,800 square meters of roof or 50 houses.)

Before the paint job, the team measured the temperature of the roof surface and undersides, rooms and surrounding.

“We gave the residents one week to acclimatize with their new colored roof. We measured the temperature again after one week,” Lucero explains.

She, however, notes that in order to achieve the most desired result—lower temperature—the roofs of most, if not all, houses must be painted white. “Heat among buildings is contagious. If the neighboring building is hot expect that the nearby building will also get some of the heat,” she says.

Lucero acknowledges that the rains made it difficult for her team to determine if the fresh paint had made any changes in humidity inside the houses.

Although the group had yet to present the results of its experiment, the proposal drew the nod of the judges in the Youth Climate Change Project because it can be done even at the household level.

As winners, the students took home P15,000, which they can use as seed money to implement their small household solution. The amount, however, is not enough to achieve its goal of painting 1,800 square meters of roof, which could cost more than P50,000.

To generate more funds and support, the group presented its proposal before 100 young people during the Youth Environmental Summit at University of Cebu (UC) on March 12.

It caught the attention of Cebu City Councilors Nida Cabrera and Alvin Dizon, says project volunteer Christian Borg dela Serna.  The city government, through Cabrera’s office, donated P20,000 for the project implementation.

Dela Serna says Smart then asked the UC College of Law to help out.

“We helped them get the support of the city government, then partner with NVIRO, which is an environment-friendly paint brand, and provided us with the paint at discounted price,” he says.

The long-term plan, he says, is to encourage companies to support the paint-your-roof-white movement.