Green buildings incorporate many elements of design that help reduce energy spending, mitigate negative environmental aspects and improve the health and well-being of the people who live and work inside. One element of green design that provides all of these great benefits is a cool roof. Cool roofs have been around for quite some time, and they continue to grow in popularity as the roofing material of choice for home-owners and business who care about the environment. Despite the many benefits and real financial savings that cool roofs offer, according to the U.S. Environmental Protection Agency, 90% of ALL roofs in the U.S. are still dark colored. This is in part due to aesthetic preferences, but mostly it is due to a lack of consumer education on the benefits of cool roofs, as well as the variety of color and style choice available in the cool roof building materials.
What is a Cool Roof?
It is a misconception that a cool roof needs to be white in order to have its cool properties. A cool roof is one that reflects sunlight and radiates absorbed heat as light energy back to the atmosphere, instead of transferring absorbed heat to the building below (this is what a black roof does). Both properties are measured as a fraction or percent, and the higher the value, the “cooler” the roof. There is no universally accepted definition for a cool roof in terms of reflectance and emittance.
Obtaining a rating for a cool roof material
Minimum requirements of what material can be considered a cool roof are set by organizations that maintain building codes and voluntary green building programs. When you are looking for cool roofing materials for your home or office, you should consider obtaining information from such an organization. For example, the Cool Roofing Council, established in 1998 is an independent, non-profit rating entity that measures roofing product surfaces for radiative properties. Through the Cool Roofing Council, roofing product manufacturers and sellers can measure their products’ radiative properties. Tests of cool roofing material samples are conducted in the Cool Roofing Council’s independent laboratories. Manufactures can also get their cool roofing products listed on the CRRC’s online Rated Products Directory. Moreover, the Cool Roofing Council also provides third-party verification of radiative property data on roofing products, which is a really useful tool for consumers who are looking for the right cool roof technology.
Cool Roofing Choices
Today, cool roof technology is highly advanced, and cool roofs come in a variety of different colors, including dark colors, made possible by the cool color technology, which uses dark-colored pigments that are highly reflective in the near-infrared (non-visible) portion of the solar spectrum. Moreover cool roof technologies now come in a great variety of roofing products such as shingles, tiles, metal roofing, modified bitumen, field-applied coatings, or cool flat single-ply membranes roofs. You can be sure that there is a “cool” version available that will meet your aesthetic and energy saving needs.
Benefits of Cool Roofs
The US department of energy has conducted a careful analysis of the benefits of cool roofs and has found that cool roofs save money while helping the environment. If you have a roof and its black, its absorbing energy from the sun, and its getting hot, and it increases air conditioning bills. If you have a white or a reflective roof that scatters back the visible radiation, of course it reduces your energy consumption. The really incredible thing about a cool roof is that it also reflects that energy back into space. As a result, there is very little green house gas effect for visible light. It is the heat light that is being trapped by carbon dioxide, the water vapor and other gases. As a result, a cool roof helps keep the earth cool as well; it not only your home that is being cooled, the earth is also being cooled. This evidence has lead The US department of energy to launch an initiative where it is installing cool roofs whenever financially possible.
Moreover, research has shown that cool roofs can extend the lifespan of a roof, which in turn helps cut maintenance costs and reduces the creation of unnecessary waste. Regular roofing material wear out as a result of extreme daily cycles of infrared (IR) radiation, ultraviolet (UV) radiation, and moisture penetration. On the contrary, cool roofs reflect the UV and IR radiation, and keep the roof at a more constant temperature. As a result, they are able to slow down the rate of degradation.
Ultimately, as we transition to cleaner sources of energy, the cleaner source of energy is one you do not have to generate in a way that negatively impacts your lifestyle and our earth. Installing a cool roof is one way to make this happen, while also enjoying the immediate personal benefits of lower energy and maintenance bills.