Urban areas all over the United States are getting hotter. This state of affairs has given rise to a vigorous dispute over the adoption of cool roofs. Materials can be more than 50 degrees cooler than traditional dark roofs on hot summer days. This cooling effect would be a big step in mitigating extreme urban heat. Baltimore’s recent passage of a cool-roof ordinance in early 2023 provides one of the most recent entries into this budding discussion. The city joins at least eight states and more than a dozen municipalities that have adopted similar requirements, highlighting the increasing awareness of the impact roof color has on urban heat.
Roofs account for approximately one-fourth of the surface area in large U.S. cities. Their color is an often overlooked, yet extremely important, feature in determining local climates. Research proves that cool roofs have a high solar reflectance. This important reflection prevents the sun from being absorbed, preventing heat build-up and keeping overall temperatures cooler in cities. This bold initiative has not been without controversy. Yet throughout the first half of the 2020s, industry groups have lobbied for this established science to be upended. They argue that the benefits aren’t as large as proponents say they are.
The Science Behind Cool Roofs
A new study shows just how life-saving an impact reflective roofs can have. It even estimates that these roofs would have saved more than 240 lives during London’s heatwave in 2018. This study further strengthens the case for adopting cool roofs in locations that experience severe heat. Indeed, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) now prescribes using reflective roofs in commercial buildings. This guidance is focused on climate zones 1, 2, and 3—home to most of the southern and southeastern U.S.
Yet associations such as the EPDM Roofing Association and Asphalt Roofing Manufacturers Association (ARMA) have both questioned the credibility of these findings. Even with the task force’s recommendations, critics aren’t buying it. Ellen Thorp, representing ARMA, stated, “Current research does not support the adoption of cool roofs as a measure that will achieve improved energy efficiency or reduced urban heat island.” Such claims have ignited discussions around the country of whether such measures should be required nationwide or even in all climate zones.
Beyond the temperature impact, there are valid concerns with the financial return on cool roof installations. First, cool roofs reduce the need for air conditioning in the hottest months. The new standards could result in increased heating costs in the colder months. Researchers argue that in most cold North American climates, the energy savings during summer months typically outweigh any additional heating costs incurred during winter.
Local Initiatives and Community Impact
The cool roofs campaign received a significant boost when Baltimore became the first city in the nation to adopt a cool-roof ordinance this past July. Homeowner Owen Henry covered his roof in white reflective material for $100. As a result, he observed an incredible 24% decrease in his electricity consumption. He expressed strong support for such initiatives: “Phooey to any manufacturer that’s going to try and stop us from maintaining our community and making it a pleasant place to live.” His experience is a powerful example of how what we do as individuals can lead to greater benefits for the whole community.
Not every response to a cool roof mandate has been so uplifting. Brian Spear, a local contractor, commented on the potential restrictions posed by these laws, saying, “If someone told me you couldn’t put a dark roof on your house … I’d understand.” Despite his reservations, he acknowledged the importance of addressing community needs: “I’m all about it being for the common good.” Photo by Scott Lewis on Unsplash His comments capture the current push and pull of private homeowner choice versus public, environmental stewardship.
The argument has spread well beyond the city of Baltimore, to other localities where these types of ordinances have been proposed or adopted. Tennessee recently repealed that very requirement from their law for reflective roofs on commercial buildings. Officials stressed the importance of taking a “whole building approach” to maximizing energy efficiency. This echoes larger fears that generic, catch-all solutions aren’t cutting it when it comes to navigating climate change’s widespread adaptation — erosion, drought, and flooding — unique regions.
Industry Pushback and Future Considerations
Opponents of cool-roof ordinances have raised these kinds of concerns on the grounds that government regulations should not interfere with consumer choice. Thorp mentioned that her organization has been able to lobby successfully against such mandates reaching into climate zone 4 and 5. She stressed the importance of considering regional differences when implementing such measures: “A one-size-fits-all approach doesn’t consider climate variation across different regions.”
Now, industry groups and advocates of cool roofs are at odds. This sink or swim tension creates an important teachable moment, balancing extreme environmental goals with complicated economic realities. Bill Updike, an advocate for cool roofs, pointed out the stark difference in temperature between dark and reflective surfaces: “You can physically burn your hands on these roofs.” Such proclamations serve as a clarion call for communities to invest in interventions that combat urban heat.
As cities need to adapt to climate change and rising temperatures more than ever, the fight over cool roofs is sure to heat up. Stakeholders from various sectors must navigate this complex landscape to determine effective policies that promote sustainability while respecting individual rights and economic considerations.