Why Cool Roofs Are Hot

Page 1

In a world where trapped heat is causing

all sorts of ecological issues, it is a small wonder that cool roofs are steadily gaining ground. The simple yet revolutionary way these roof systems reflect the sun’s radiation (solar reflectance) and release heat to the surrounding atmosphere (thermal emittance) has opened up a whole suite of advantages for residential and commercial property owners. Below are three of their biggest benefits.

Part One:

Energy Savings

ENERGY STAR estimates the annual costs

for air conditioning in the US to be around $40 million. Because cool roofs reflect up to 65% of the heat they absorb, they are able to take a huge load off your cooling systems. In the summer months, this can produce as much as a 50-degree difference between a space under a cool roof and one under a traditional roofing system. Your property’s peak cooling demand can be reduced by 10 to 15 percent. The end result? Considerable energy (and money!) savings.

On a bigger scale, cool roofs also help mitigate the cooling loads on entire communities, even cities. They do this by reducing the heat island effect. When there are more cool roofs in your area, more sunlight is reflected and less heat absorbed, resulting in lower energy consumption and better overall comfort in metropolitan communities. To maximize the energy savings you could get from a cool roof, take the following factors into consideration:

• Your building design • The climatic conditions in your area • The type of insulation in your property (and whether or not you can improve it) • Your building envelope’s energy efficiency

Bonus Tip: Free online tools such as the

Roof Savings Calculator (RSC) by Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory can help you estimat annual energy savings based on your property’s heating and cooling loads. You can also consult the ANSI/CRRC-1 Standard for more information on the solar reflectance and thermal emittance of different roofing products.

Part two: Extended Roof Service


Choosing a cool roof also means less time

and money spent on maintenance and replacements. Research has shown that cool roof products can extend the life and functionality of residential and commercial roof systems by slowing down their degradation. Daily doses of ultraviolet and infrared radiation— not to mention exposure to the elements—can prematurely wear out the components of your roof. Because cool roofs reflect back most of the radiation they receive and achieve thermal equilibrium faster than traditional roofs, the harmful effects of heat-induced expansion and contraction on your roof are reduced.

How to Make Your Existing Roof Cool Much of what makes a roof cool depends upon the surface that receives the most exposure to the sun. There are more than 500 roofing products available on the market today, each of which is best suited to specific applications. This means that property owners who want to maximize their buildings’ energy efficiency via cool roofs are nowhere near limited in terms of material choices.

Low-Slope Roofs a.

Single-ply membranes. Available in TPC, PVO, or EPDM formats, single-ply membranes are pre-fabricated sheets that are rolled onto a roof and attached using mechanical fasteners. TPC and PVO membranes are usually white, while EPDM is black. To boost these membranes’ solar reflectivity and infrared emittance, white acrylic coatings may be applied.


Modified bitumen sheet membranes. These products combine plastic and rubber membranes with other reinforcing fabrics. They are pre-coated at the factory and/or covered with mineralized granules to increase their reflectance and emittance capacities.

Steep-Slope Roofs a. Shingle roofs. Shingle roofs are made from a wide variety of materials, including fiberglass, wood, polymers, and metals. They use specially coated granules to boost their reflective and emittive properties. b. Tile roofs. Certain types of tile roofs have

natural cooling properties. Those that don’t perform as well can be improved with the help of glazing and/or special reflective coatings.

c. Metal roofs. Metal roofs are a cool roof mainstay. While standing seam is the configuration most often used, metal roofs also come in other profiles such as shingles and shakes. White metal roofs are the poster child of cool roofs; however, paints with special additives have been developed to allow more color choices without compromising reflectance.

Part three:

Increased Property Value

Every roofing project is centered around a specific goal—one of achieving or increasing a particular good, be it energy efficiency, functionality, even “mere” aesthetics. The fact that cool roofing products are now available in a broad range of colors, textures, and profiles has made it easy for property owners to find the right material to complement the architectural design of their homes and buildings.

A cool roof ticks all the boxes. Because the benefits cover everything from curb appeal to performance and energy savings, a cool roof automatically places a higher price tag on your property. And with green building becoming more and more important for homeowners, your chances of generating buyer interest will also increase should you decide to sell.

Quick Facts • Researchers from the University of California, Berkeley and the University of California, Los Angeles found that “green” properties sold for at least $8,400 more than their more traditional counterparts. • Federal tax credits are awarded to properties that implement energy-saving building practices and technologies. This is a plus for commercial property buyers who want to save on their longterm operational expenses. • The Sensible Accounting to Value Energy (SAVE) Act, which was reintroduced in a bipartisan energy bill pending in the Senate, will require lenders to factor in energy savings when granting mortgages. This means that you won’t have to lower your asking price just to sell your property, because buyers themselves will have access to more flexible payment options.

What’s the Catch? Cool roofs certainly sound good, but are they too good to be true? The biggest issue surrounding cool roofs is their performance in colder climates. When it snows, their capacity for absorbing less heat might be a negative. So are they still worth it? Experts advise homeowners to examine their energy savings during summer and see whether or not it can compensate for the added heating load during winter. Most estimates show greater year-round energy cost benefits for properties with cool roofs. For added efficiency, consider improving your insulation and increasing your building envelope’s thermal performance. Remember that no matter how awesome your cool roof may be, it is, after all, just part of a whole.

Tedrick’s Roofing, Inc. 37220 188th Ave SE Auburn, WA 98092

(206) 824-3440


Sources: http://coolroofs.org/documents/Cool_Roof_Ratings_Codes_and_Programs021710.pdf http://energy.gov/energysaver/articles/cool-roofs https://www.energystar.gov/certified-products/detail/roof_products http://www1.eere.energy.gov/femp/pdfs/coolroofguide.pdf http://www.today.com/home/home-energy-improvements-pay-you-back2D79709829 http://thehill.com/opinion/op-ed/206555-energy-efficient-homes-should-comewith-better-mortgages

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