Cool roofs are a great Economical way to Improve a Building's Energy Efficiency

With new California green building mandates, building owners are starting to take building green more seriously.  In an ever expanding green marketplace, there are many different products and procedures available to increase the energy efficiency of your home. One basic highly effective step that a home or building owner can take is the “cool roof,” which can be implemented rather easily and at a very reasonable cost. Black and dark-colored roofing materials can dramatically increase a building's cooling load, while cool roofs reflect the sun's radiant energy before it penetrates into the interior of the building, reducing the load.

Cool roofs are roofs consisting of materials that very effectively reflect the sun's energy from the roof surface. Cool materials for low-slope roofs are mainly bright white in color, although non-white colors are starting to become available for sloped roof applications. Cool roofs must also have high “emissivity,” allowing them to emit infrared energy. Bare metals and metallic coatings tend to have low emissivity and are not considered cool materials.

White reflective coatings used in some cool roofs contain transparent polymeric materials, such as acrylic, and a white pigment, such as titanium dioxide (rutile), to make them opaque and reflective. These coatings typically reflect 70 to 80 percent of the sun's energy. Despite the white appearance, these pigments absorb the 5 percent or so of the sun's energy that falls in the ultraviolet spectrum. Thus, the pigments help protect the polymer material and the substrate underneath from UV damage. As long as the coating is white or light-colored, the roof will have high reflectance and emittance levels.

Energy-efficient, cool roof systems can significantly reduce roof temperature during the summer, and thereby reduce the building's energy requirements for air conditioning. Some specific benefits of cool roofs are:

* Saving on annual electricity bills by reducing summer air conditioning costs.
* Saving peak electricity demand costs if you have time-of-use metering.
* Reducing roof maintenance and replacement expenses by extending roof life.
* Increasing indoor comfort in summer by reduction of infrared conversion from visible light.
* Reducing the "heat island effect" in cities and suburbs.
* Reducing air pollution and smog formation.
* Reducing roofing waste added to landfills.

There are four broad categories of roofing materials that can be used to upgrade a roof's reflectivity to 'ENERGY STAR' levels: metal, tile, roofing membranes and reflective coating. Of the four, a reflective coating may be the most economically achievable for existing buildings because it doesn’t require any significant retrofitting of the structure, which can be costly and time-consuming.

Exact energy and money savings for each type of cool roof will depend on a number of factors, such as the type and efficiency of insulation in the ceilings and exterior walls, the windows, the efficiency of the cooling system, and most importantly, the climate of the building's location.

A reflecting cool roof coating, such as Coat’N’Cool can lower interior temperature of a commercial or industrial building by 8-12 degrees during the hottest four hours of a summer day, noon to four in the afternoon. Not only does the lower interior temperature help reduce energy costs, it also improves worker productivity by creating a working environment that is more comfortable at a lower cost.

AUTHOR BIO:

Michael Magallanes is vice president of Coat’N’Cool, a cool roof product. He can be reached at [email protected]

Other cool roof products:

Hanson Roof Tiles
MCA Cool Roof Tiles
MonierLifetile Cool Roof Tiles