At GC Roofing, one of our priorities is to make sure our customers understand just how vital having a cool roof is. Of course, all roofs are cool for us, and everyone should always get just as excited about roofs as we do. But when we refer to a cool roof, we are not just talking about its awesomeness. We are talking about the roof’s ability to reflect more sunlight and absorb less heat than a standard roof.
Having a cool roof means a highly reflective type of paint, a sheet covering, or highly reflective tiles or shingles cover the entire roof surface. Think of it in terms of wearing light-colored clothing to keep cool on one of those hot summer days.
Did you know that standard or dark roofs can reach temperatures of 150°F or more in the summer sun? A cool roof can keep that same roof 50°F cooler, reducing the buildings’ energy and saving building owners and tenants money by using less air conditioning.
Nearly any type of building can benefit from a cool roof. Below is an illustration depicting the energy flow of sunlight hitting a conventional flat roof (left) and a cool roof covered with a white membrane or coating (right) (SIKA).
Source: Image 1 – Energy Flow of Sunlight on Flat Roof
That extra heat can add up.
The benefits of installing a cool roof go far beyond waterproofing. The California Department of Energy (DOE) began researching the benefits of cool roofs for energy savings and reducing temperatures in the summer for urban cities in 1980. For over four decades, researchers have studied what is referred to as the urban heat island effect. These studies have found that urban areas can be hotter due to the cumulative effect of additional heat from darker surfaces being warmer than lighter colored surfaces and emit extra heat (Yale, 2016). The concentration of buildings and roofs, dark pavements, etc., in urban environments, creates an atmosphere where the heat absorbed during the day can’t cool back down to the baseline temperature overnight. This is what has become known as the heat island effect. This problem can be exacerbated in cities where roofs and pavements typically constitute about 60% of the surface area. This heat island can affect communities due to an increase in summertime peak energy demand, air conditioning costs, air pollution, and greenhouse gas emissions. It can also create conditions that cause heat-related illness, mortality, and poor water quality. (EPA)
For building owners, this extra heat can add up. It requires additional energy to be used to cool buildings off in the summer. It can result in additional expenses to maintain air conditioning. This elevated demand can also strain the electrical grid on a hot summer afternoon, making it more susceptible to brown-outs and black-outs. Additionally, this extra heat can add to CO2 emissions, accelerates the formation of smog (ozone) from airborne pollutants like nitrogen oxides and volatile organic compounds. The increased outdoor temperature also reduces general comfort and productivity because lower air quality can aggravate heat-related and respiratory illnesses.
Take a look at this Interactive rooftop reflectance map for California cities.
https://heatisland.lbl.gov/coolscience/cool-roofs
As cool roofs are applied and installed on buildings throughout the state, the Urban Heat Island can be mitigated. This strategy can bring many benefits like reduced energy use, reduced air pollution and greenhouse gas emissions, and improved human health and comfort. This process does not happen overnight, flat roofs are generally only replaced every 15 – 20 years, resulting in a replacement rate of 5 – 7% per year. Historically, flat or low-sloped roofs were only turned into cool roofs by coating them white, typically after the existing surface’s useful life. However, with the advancement of technology, there are now “cool color” products on the market that use darker-colored pigments that are highly reflective in the near-infrared (non-visible) portion of the solar spectrum
Take a look at the temperature differences between a roof without a cool roof and a cool roof.
Image 3 – Cool Roofs Temperature Difference
Our Response
At GC Roofing, we are proud of the fact that our founder Gerry Thiesen was a part of the central valley’s energy committee and was a significant contributor to the state’s cool roof solutions. Throughout the 90’s it was typical for GC Roofing to use software programs to help building owners calculate the potential energy savings on buildings with cool roofs versus the standard roof. As technology and production efficiency have improved over the years, GC Roofing has strived to adapt accordingly. In 2005, California’s adoption of cool roofs required building owners to meet cool-roof requirements based on specific building code; Building Energy Efficiency Standards, Title 24, Part 6, designed to combat the increasing heat island effect throughout the state. The new section specified that building owners were responsible for using energy-efficiency standards that were designed to make the state’s energy usage more responsible and sustainable. Title 24 was not a new requirement, in fact, it was introduced in 1978, but these additional standards had a significant impact on the roofing industry.
Since 2005, Title 24 has continued to be updated every three years to incorporate the latest research, design, and trends to building systems like lighting, HVAC, and roofing. Currently, cool roof requirements are triggered when either 50 percent of the roof area or more than 1,000 sq. ft., whichever is less, is replaced. The cool roof requirements for re-roofs are the same as for new construction.
GC Roofing has experienced firsthand how efficient energy use can have many benefits for building owners. For over 40 years, we have seen how our cool roofs have reduced energy costs, improved building comfort and aesthetic appeal, and reduced adverse environmental impacts.
We are proud to be doing our part to help businesses save money, make electrical systems more reliable, and protect the environment. Contact us today to get information on the variety of “cool roof” and “cool color” product types we install.
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References
Cool Roofs | Department of Energy. https://www.energy.gov/energysaver/design/energy-efficient-home-design/cool-roofs
Heat Island Compendium | Heat Island Effect | US EPA. https://www.epa.gov/heatislands/heat-island-compendium
How is Energy Efficiency of Cool Roofs Measured?. https://www.sika.com/en/knowledge-hub/cool-roofs-and-energy-efficiency.html
NYC has a “cool roof” program. Is there a white paint or …. https://www.greenhomeguide.com/askapro/question/nyc-has-a-cool-roof-program-is-there-a-white-paint-or-coating-to-make-my-roof-cooler
Urban Heat: Can White Roofs Help Cool World’s Warming …. https://e360.yale.edu/features/urban-heat-can-white-roofs-help-cool-the-worlds-warming-cities
