Cool Roofing: An Innovative Solution to Combat Urban Heat Islands
- joelkohli8
- Jan 21
- 5 min read
Updated: Jan 27
In the context of accelerated climate change, cities are increasingly facing a concerning phenomenon: Urban Heat Islands (UHIs). This phenomenon is characterized by significantly higher temperatures in urban areas compared to surrounding rural zones, a direct consequence of dense infrastructure, pervasive concrete, and a lack of green spaces. To address this challenge, innovative solutions are emerging, with Cool Roofing standing out for its effectiveness in lowering roof temperatures and contributing to better urban heat management.
Understanding the Urban Heat Island Phenomenon
Urban Heat Islands (UHIs) result from several interconnected factors. In urban environments, construction materials such as asphalt, concrete, and dark roofs absorb and store solar energy, releasing it slowly as heat. This thermal buildup, combined with heavy traffic and a lack of green spaces, creates urban microclimates where temperatures can be up to 10°C higher than in surrounding rural areas. The consequences of these UHIs are numerous: increased energy consumption for cooling buildings, heightened air pollution, and negative impacts on residents' health.
Cool Roofing: A Key Tool to Mitigate Urban Heat Islands
Cool Roofing offers a straightforward yet highly effective solution to combat urban heat islands (UHIs). This technology involves applying special reflective coatings to rooftops, designed to reflect solar rays rather than absorbing them. The principle is based on three key physical properties: reflectivity (the ability of the roof to reflect sunlight), conductivity (reducing heat transfer into the building), and emissivity (the ability of the roof to quickly release accumulated heat).
Reducing Building Temperatures
Thanks to its thermo-reflective properties, Cool Roofing significantly lowers rooftop temperatures — sometimes by as much as half compared to conventional roofs during periods of intense heat. This temperature reduction directly improves indoor thermal comfort, making buildings cooler and more pleasant for occupants. With less demand placed on air conditioning, these systems operate more efficiently, resulting in substantial energy savings.
Mitigating Overheating Effects in Cities
By lowering rooftop surface temperatures, Cool Roofing reduces the amount of heat absorbed by buildings, thereby limiting heat radiated back into the atmosphere. Buildings with cool roofs contribute to cooling the surrounding urban air and mitigating UHIs. This overall decrease in neighborhood temperatures enhances the quality of life for residents, notably by improving public health conditions.
Reduction of Air Pollution and Energy Consumption
Urban Heat Islands (UHIs) also contribute to higher air pollution levels, as elevated temperatures increase the formation of secondary pollutants, such as tropospheric ozone. By reducing the intensive use of air conditioning systems, Cool Roofing helps lower greenhouse gas (GHG) emissions, contributing to cleaner air and a more environmentally friendly energy balance.
Cool Roofing and Sustainable Development: A Versatile Approach
Beyond combating UHIs, Cool Roofing fits perfectly within a sustainable development strategy. By reducing energy needs and CO2 emissions, this solution supports the goals of cities aiming for carbon neutrality and aligns with energy transition policies. Additionally, the materials used in thermo-reflective paints are often durable and UV-resistant, prolonging the lifespan of roofs and thus reducing long-term maintenance costs.
Complementary to Photovoltaic Panels
Another unique aspect of Cool Roofing is its ability to improve the efficiency of photovoltaic panels. By installing bifacial panels on reflective roofs, it is possible to leverage the albedo effect to maximize solar installation efficiency. The light reflected by thermal roofs is reused by the solar panels, improving their performance and contributing to increased energy production.
LONGi Green Energy Technology, in collaboration with the German testing center TÜV Rheinland, published a six-month study conducted on a pilot installation of bifacial modules in Chennai, India. The study reveals that bifacial modules, including mono PERC and n-type bifacial models, provide an energy yield gain of approximately 20% compared to monofacial modules. This gain is partly attributed to the albedo effect, amplified by the placement of white gravel beneath the panels, which reflects light toward the back side of the modules. The data shows that this albedo effect is particularly beneficial on cloudy days, where diffuse light promotes increased production. The n-type bifacial module without a frame achieved a 0.76% higher yield compared to the framed model, as the absence of the frame reduces shading on the back side. This installation provides valuable data for modeling and optimizing the yield of bifacial installations, which are highly sought after by energy model developers.
Towards Widespread Adoption of Cool Roofing in Urban Areas
Today, more and more cities around the world are adopting Cool Roofing to combat the harmful effects of UHIs. Integrating this solution into urban construction and renovation programs provides a simple, effective, and cost-efficient way to address climate and energy challenges. In Switzerland, for example, some cities have started rolling out initiatives to encourage the installation of cool roofs, particularly on public or high-traffic buildings, such as schools and hospitals.
ClimaCoolor, a Partner for a Cooler and More Sustainable Future
Cool Roofing represents a valuable advancement for cities looking to mitigate the impact of UHIs. By integrating this solution into urban projects, municipalities can provide their citizens with a more comfortable and energy-efficient living environment. At ClimaCoolor, we believe that Cool Roofing is key to building more resilient and healthier cities while reducing energy costs.
To learn more about how Cool Roofing could transform your city, contact us: together, let's cool the cities of tomorrow.
By Joël Kohli, Chief Operating & Sales Strategy
Sources :
United States Environmental Protection Agency (EPA)
The EPA presents the principles and benefits of reflective roofing to reduce the effects of urban heat islands.
Source : EPA.gov - Cool Roofs
ScienceDirect (Groupe Elsevier)
ScienceDirect is an online platform for publishing and accessing scientific articles, managed by Elsevier, one of the largest scientific publishing houses in the world. This platform provides access to an extensive database of publications covering a wide range of disciplines, including life sciences, physical sciences, medicine, engineering, social sciences, and humanities.
Lawrence Berkeley National Laboratory
This American research laboratory analyzes the thermal effects of cool roofs and their impact on urban energy consumption.
Source : lbl.gov
Ministère de la Transition écologique, de l’Énergie, du Climat et de la Prévention des risques (France)
This ministry provides an overview of initiatives and solutions for French cities, including the installation of cool roofs.
Source : ecologie.gouv.fr
Sika Group
Sika is a Swiss company that produces construction materials. Active globally in the field of specialty chemicals, it is a supplier in the areas of sealing, bonding, sound insulation, reinforcement, and structural protection. Sika is represented in 94 countries with over 170 production and sales sites.
Source : sika.com
LONGi Green Energy Technology Co.
Founded in 2000, LONGi Green Energy Technology Co., Ltd. (LONGi) is committed to being the world's most valuable solar technology company.
Guided by its mission "use solar energy, create a green world" and its brand image of "robust, reliable, and cutting-edge technology," LONGi develops solutions for large-scale power plants, as well as for industrial and residential sectors, relying on an innovation-driven approach. Ultimately, our ambition is to also provide "Green Energy + Green Hydrogen" solutions for a global zero-carbon development.
NYC MyCity – CoolRoofs
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