Cooling It Down: Lower Energy Bills with Cool Roofs

Cool roofs are a simple and effective approach to lowering the cooling energy loads of buildings and for increasing occupant comfort. By reflecting solar radiation, cool roofs reduce the amount of sunlight that is absorbed as heat in a building. As a result, the need to control indoor air temperatures with air conditioning systems (A/C) decreases, which in turn lowers energy bills.

In addition to energy cost savings, cool roofs contribute to grid stability by lowering the need for A/C use during the hottest times of the year. Cool roofs also reduce outside ambient air temperatures, which helps mitigate the urban heat island effect, a phenomenon where cities can become several degrees hotter than surrounding less developed areas.

Cool Roofs: The Basics

A "cool roof" is any roof surface comprised of highly reflective materials that keep the sun from heating up a building. At RAMCON, we install cool roofing options in almost any roofing material, and innovations in product formulation have enabled us to install systems in a variety of colors as well.

The performance of these materials is rated based on two radiative properties: solar reflectance (SR) and thermal emittance. The reflectivity of a roof’s surface is important because on hot, sunny days, standard dark roofs can be up to 90°F hotter than the ambient air temperature.

 

Cool Roofing Considerations

As with any building envelope strategy, there are several factors to take into account when considering the installation of a cool roof. While cool roofs are ideal for many buildings, their success depends on several factors, including the attributes of a building and the scope of the project. In general, cool roofs have the most benefits for facilities in very hot climates like ours that rely significantly on the use of A/C to control indoor ambient air temperatures and on facilities with little insulation, such as some warehouses.

• Project scope. Cool roofing options vary greatly based on whether the project is a new construction, complete reroof, or renovation of an existing roof. Examples of renovation options include coating an existing flat roof with a cool or light colored coating or installing a single-ply roofing system over an older metal roof.

 

• Facility specifics. Roof slope, location, and size greatly impact the reflective properties of a cool roof. Because low slope and flat roofs cannot be seen from street level, highly reflective, smooth, and bright white materials can be used without visually impacting the surroundings.

 

In addition, other building factors are important to consider, such as the number of floors and the amount and type of insulation. Cool roofs have the most impact on the upper floors of a building, with cooling energy savings between 15% and 25% for the top floor and savings of 5% to 10% for the next floor down. Unfortunately, there is usually less of an impact on overall cooling loads for high-rise buildings.

 

• Other roofing material factors. Our team at RAMCON considers many factors when selecting the right system for your facilities, such as compatibility with existing roof systems, ease of maintenance, and warranty requirements.

 

Cool roofs are an optimal approach to reducing the cooling-energy load of buildings, particularly during the hot summer months when A/C demand is high. The benefits of reduced energy usage from cool roofing materials includes lower energy bills, energy grid stability, and cooler environment overall.