White ceilings absorb much less heat, the interior of your home will stay cooler, reducing the need for air conditioning. Another way to keep your home cool if you live in a warm climate is to use window inserts that block UV rays. These roofs do much more than keep your back out of the sun. While the term cold roof is sometimes used to describe any roof surface that is cooler than a standard roof, green certification programs such as LEED, Energy Star, and the Department of Energy's Building Technology Program base their respective credentials for cold roofs on the ability of the roofing material to reflect the sun (solar reflectance) and release absorbed heat (emissivity).
They also meet Chicago's cold roof standards, which has been one of the first to adopt rooftop gardens and other green roofing technologies. Ballast roofing systems are relatively inexpensive, and ballasted areas can be combined with roof gardens to reduce the total cost per square foot of a landscaped roof. Green roofs protect buildings under direct sunlight and lower both surface temperatures and surrounding air temperatures through evaporation and transpiration, processes by which plants remove moisture from the soil and emit it through leaves. However, simply applying a white coating to the surface of the material in the factory can increase solar reflectance until acceptable standards for cold roofs are reached.
For example, researchers at Arizona State University who modeled the long-term effects of cold roofs showed a 4 percent decrease in local rainfall. In its most basic form, a roof misting system can consist of little more than a garden hose adjusted to the fog temperature and directed to the other side of the roof. As a property owner or manager, keeping an eye on roof maintenance will save thousands of dollars. Knowing when to replace roofs at the right time can decrease the chances of material failures that can cause leaks, holes, structural degradation, etc.
Ultimately, your roofing options will depend on the extent of your roof renovation project and the type of roof you have. Ballast roofing systems are roofs in which a membrane is placed on the roof cover and then held in place with the weight of concrete paving stones or natural stones. If you live in a hot climate or have hot summers, it's time to think about what you can do with your roof to cool your house down. While not used as much as roof tiles, both traditional and cool-colored roof tiles can be good options for cooling a steeply sloped roof. If you prefer to enjoy the benefits of a fresh roof without having to add new materials or coatings to the surface, consider using a spray cooling system for roofs.
If cost is the most important factor when choosing a cool roof, Supreme tiles from Owens Corning are a good option. Cold roof coatings are sprayed, rolled or brushed onto an existing flat or low-sloped roof to create a bright white reflective surface similar to paint. Tests show that some roof coatings, such as elastomeric coating and ceramic coating, provide high levels of solar reflectance of more than 80%.
