By Kyle Ziebarth
Cool roofs (also called white roofs) have become a popular upgrade for commercial and industrial buildings around the world. These highly reflective roofs offer numerous advantages that reduce energy costs associated with cooling a building. They also help to mitigate what is known as the “urban heat island effect,” a phenomenon where urban areas experience higher ambient temperatures than surrounding rural spaces due to the presence of heat-absorbing surfaces like rooftops and parking lots.
Crucially, cool roof coatings are an efficient and economical solution that can be applied over many types of existing roof systems. These coatings are long-lasting and can help building owners create significant long-term energy savings, reduce maintenance spending, and earn Inflation Reduction Act (IRA) energy credits and tax deductions.
In this article, we will answer facility owners’ and managers’ frequently asked questions by exploring the growing trend of cool roofs, their benefits for buildings, and how to get the most out of a reflective coating that can extend the life of the existing roof.
What Is A Cool Roof?
Put simply, a cool roof reflects sunlight and is designed to stay cooler in warmer weather. Cool roofs can be constructed from materials that include membrane systems (rolls of modified bitumen, for example) as well as asphalt, stone/rock, and metal roofing products. However, most are created using acrylic elastomeric silicone coatings. These coatings may be installed on flat or gently sloping roofs—typical of offices and industrial facilities—as well as on steep-sloped metal roofs, such as those found on retail buildings.
The coatings are often applied to existing thermoplastic polyolefin (TPO) and polyvinyl chloride (PVC) roof membranes as well as on other common surfaces including metal, modified asphalt, and spray polyurethane foam roofing systems. These are applied by either spraying or rolling the coating over the existing roof surface. The rubbery material naturally conforms to the surface and expands and contracts with the building’s structural changes due to temperature or pressure fluctuations, thus helping maintain the integrity of the roofing system over time.
Acrylic and silicone are popular materials used to make cool roof coatings due to their strong UV resistance and high reflectivity (between 80%–90% solar reflectance; a reflectance value >50% is considered a bright coating). Acrylic coatings tend to cost less than silicone coatings, however, silicone products typically last longer than acrylics due to their inherently superior UV and moisture resistance. Both are viable options for most commercial and industrial buildings.
What Are The Benefits?
Cool roofs reflect the sun’s rays away from buildings instead of absorbing them. This can reduce the amount of energy used for cooling during peak summer months. A California study found cool roofs stay up to 50–60 F° (28–33 C°) cooler than conventional roofs during peak summer weather and provide an average yearly net savings of almost 50 cents per square foot. This figure includes the potential price premium for cool roofing products and increased heating costs in the wintertime balanced against summertime energy savings, savings from downsizing cooling equipment, and reduced labor and material costs over time due to the longer average lifespan of cool roofs.
By lessening the urban heat island effect, cool roofs help to lower local outside air temperatures, which can slow the formation of smog from air pollutants in the environment. The cool roofs market is expected to witness a CAGR of 5.6% from 2023 to 2028 and is likely to reach $11.8 billion by 2028, up from $7.5 billion in 2022. More municipalities and companies are adopting policies that require the use of sustainable building practices and technologies which is a major factor driving its growth.
Utility incentives and government energy-efficiency rebate programs are also making cool roofs more compelling to building owners. The 2022 IRA is expanding energy-efficiency credits from 50 cents to $5 per square foot, depending on the level of energy savings and whether a building meets wage requirements. Section 179D of the IRA enables building owners to claim a tax deduction for installing qualifying systems in buildings, including implementing a cool roof solution.
Additionally, the Cool Roof Rating Council (CRRC) maintains a list of individual agencies with links to various energy-efficiency rebate and property tax credit programs, as does DSIRE, a comprehensive source of policy and incentive information by the NC Clean Energy Technology Center at North Carolina State University. Not only that, but building standards implemented through the Leadership in Energy and Environmental Design (LEED) certification program have adopted guidelines related to cool roofs that may qualify the owner for additional incentives.
What Is the Cost?
Per EPA data, the cost premium for cool roofs versus conventional roofing materials ranges from zero to 5 or 10 cents per square foot for most products, or from 10 cents to 20 cents for a built-up roof with a cool coating used in place of smooth asphalt or aluminum coating. Although costs will vary greatly depending on location and local circumstances, cool roof coatings on a low-slope roof might cost 75 cents to $1.50 per square foot, while single-ply cool roof membrane costs vary from $1.50 to $3 per square foot.
Generally, cool roofs help to reduce annual air conditioning use in buildings up to 15% according to the U.S. Department of Energy. Additionally, long-term maintenance costs can be reduced as HVAC units do not have to expend as much energy to cool the building during periods of peak demand.
For building owners, the CRRC—an independent, nonprofit organization that maintains a third-party rating program for cool roof solutions—provides a free online savings calculator for small and medium-sized facilities that purchase electricity without a demand charge based on peak monthly load. There is also a version for large facilities that purchase electricity with a demand charge based on peak monthly load.
Furthermore, where cool roof coatings are applied over existing roof substrates, there is no need to tear off and replace the existing roof, which can significantly reduce project spending. Full roof restorations—where roofs are repaired and coated to enhance durability and extend life—typically range between $400 to $700 per square foot, while tear-off and replacement projects tend to start at $1,000 per square foot or higher, depending on region and project complexity.
Why Coat An Existing Roof?
Installing a protective coating to an existing roof system is the natural next step in the life cycle of many roofs. Importantly, roof restoration can increase the useful life of a roof from five to 20 years or more. Cool roof coatings—which can be applied like paint using only a brush, roller or sprayer—provide an easy-to-maintain surface that also reflects sunlight. Importantly, these coatings do not involve the same time, cost, or safety concerns of a full roof replacement as they can be easily reapplied after a set number of years to refresh their efficiency.
However, to get the most out of a cool roof coating, it should be applied by a professional. Not only does this ensure the job is done properly, but many manufacturers also provide warranties for up to 20 years when their products are applied by certified contractors. These contractors can also make a recommendation on the best coating solution for a particular structure.
Choose an installer carefully to ensure correct application of a cool roof coating that will maximize durability and solar reflectance. The National Roofing Contractors Association (NRCA) provides some helpful advice in its guidelines for selecting a roofing contractor. Note that all coated roofs should be properly examined at regular intervals by a professional and maintained or cleaned when necessary to ensure the maximum solar reflectance.
It Pays To Be Cool
The growing trend for cool roofs is easy to understand; by reducing energy demands and improving building temperature control, these solutions provide an effective way to make facilities more cost-efficient and sustainable. With the ever-increasing focus on curbing wasteful consumption, cool roof coatings have become part of the energy equation for many industries, giving companies another way to lower their utility bills and maintenance spending without replacing an entire roof.
Kyle Ziebarth is a Senior Manager – Lead Generation & Sales Inside Marketing at Innovative Chemical Products (ICP).
