Can a roof’s material cool the outside air and lower energy demand? A new study produced by Argonne National Laboratory says “yes.”

With increasingly warming temperatures during the summer, urban centers like Chicago must arm decision-makers and communities with information about strategies to help keep their residents cool. One approach involves something all buildings already have: a roof.

Argonne Lab - Cool Roofing Colors - Image 2.jpgTo help understand how climate affects urban communities, researchers at the U.S. Department of Energy’s Argonne National Laboratory examined three types of roofing strategies and their impact on near-surface temperature and cooling energy demand through regional modeling in the Chicagoland area.

According to the Argonne study’s results, certain roofing materials empirically demonstrated that they could help cool the surrounding air and decrease the need for air conditioning. The team ran a regional climate model simulating three types of roofs: cool (painted a heat-reflecting white), green (vegetation), and solar panels.

Argonne found that the three types of roofs reduced the near-surface temperature and AC consumption demand during daytime hours when the air temperature was the highest. Because all three strategies offer cooling effects, each reduces the overall energy consumption needed for HVAC units.

Cool roofs reduced AC energy consumption the most, followed by green roofs and solar panel roofs. Energy demand was shown to be reduced by 16.6%, 14.0%, and 7.6% when cool roofs, green roofs, and solar panel roofs were deployed, respectively.

Overall, the large-scale deployment of cool roofs showed the best potential for cooling effects and energy saving. They cost less than the other two technologies and do not require additional water.

Stakeholders, including roofing contractors and materials suppliers, can use the study results to inform sustainable development approaches, lower summertime cooling energy demand, and help minimize greenhouse gas emissions in the long term in urban heat-trapping areas.

The work was conducted as part of the Community Research on Climate & Urban Science [CROCUS] Urban Integrated Field Laboratory. Argonne leads CROCUS in partnership with academic and community organizations and civic and industry champions. Focused on the Chicago region, CROCUS studies urban climate change and its implications for environmental justice.

The results of this baseline study will help CROCUS communities plan and test mitigation options. The Energy Department said the information is a good starting point for what the researchers hope to achieve next, a city-scale and global-scale model for each roofing option.

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