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Can Asphalt Shingles Be Used On A Cool Roof?


A section of a roof with dark gray solar-reflective asphalt shingles

 

Cool Roofs are one of the new buzzwords in the roofing industry, and for a good reason. A cool roof is more environmentally friendly, makes you a good neighbor, and makes your home more energy-efficient. Many people assume that a cool roof needs to be a light color. Many people are wrong.

 

 

 

What Is A Cool Roof, Anyway?

Before we can tell you what makes a cool roof cool, we need to discuss why anyone cares in the first place.

 

The Problem

Roofs started out simply as a means to provide some shelter from the elements. They gave us shade in the day, kept the largest critters from climbing over our walls, and stopped most of the rain, and that was good enough for hundreds of years.

Then, we realized that roof structures could be used to make our homes more structurally sound, and then we developed better materials for shedding water and protecting the interior.

Eventually, we learned to let our roofs breathe with venting systems, but we didn’t concern ourselves with the heat from the roofing tiles above our heads. On a hot summer day, our roofs can heat up to 180 degrees or more.

The Result

With all that heat radiating back into our homes and turning each roof into an enormous heat sink, the effect on our community can be enormous.

Attic spaces fill with this heat, creating a tough barrier for our indoor air to penetrate. The result is top floors that are difficult to cool and an overall reduction in airflow through our homes. This insulating effect causes our climate control systems to run longer and harder, leading to increased energy usage and even plays a part in the rolling blackouts we see in the western part of the United States.

The heat sink effect raises the ambient temperature in tightly spaced neighborhoods, affecting everything in the area, from personal comfort to the health of vegetation.

 

The Solution

Aside from better venting or installing an attic fan (both of which can help), there was a growing consensus that lighter-colored roofs gathered less heat. Since darker colors reflect less light, this made sense, but it was only partially right. Light-colored roofs were less hot, but they weren’t necessarily cool.

It was then decided that the material mattered almost as much as the color. Many thought that asphalt shingles could never achieve the temperatures needed to be considered a cool roof because asphalt holds heat too well. Many were, once again, wrong.

 

Cool Roofs

Cool roofs are the result of the reflectivity of the roofing surface. However, once the roofing industry delved deep into the concept of reflectivity, it discovered that color wasn’t the deciding factor it was thought to be, nor was the underlying material.

Reflectivity is about more than the color we see with our eyes. Yes, identical materials will be cooler the lighter their color, but the material decides how much of the sun’s energy turns into heat, and a great portion of the sun’s energy can’t be seen. These unseen energies can’t show up as color, making lighter colors less important than we once thought.

 

Cool Asphalt

Asphalt is a material that is almost synonymous with heat. The last thing you want to do on a sunny day is to walk barefoot on a black-topped driveway. But what if you could keep the sun’s energy from ever reaching the asphalt?

No energy: no heat.

And that’s exactly what the roofing industry figured out. If they could reflect away portions of all the sun’s energy, seen and unseen, the asphalt in their shingles wouldn’t have any heat to soak up and push into your home.

 

Dark And Cool

Once science broke the code on thoroughly reflecting the sun’s energy, color became much less important. Yes, a white solar-reflective shingle is more effective than a dark brown one, but both are still considered a cool roof material, and both will reduce the community problem of overheated roofs.

 

Be A Hero

Now you can do your part to make the world a cleaner place. And do so without giving up your preference for the look of a beautiful dark-colored roof. Plus, you can do it relatively cheaply by using durable, inexpensive asphalt shingles instead of the more expensive alternatives of years gone by.

With the advanced technology of solar-reflective coatings that are now available for high-grade asphalt shingles, being a good citizen is an easy and relatively inexpensive choice to make.

If you think it is time to do your part, or you just want to save on energy costs, contact us at Jancewicz & Son for a free estimate on a new cool roof for your Greater New Hampshire area home.

 

 


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