During the scorching summer months, your roof temperature can easily exceed 150 degrees F. This can potentially cause damage to the shingles on your roof, and it raises the costs associated with cooling your home. Cool roofing can lower a roof’s surface temperature by 50 to 60 degrees, according to the EPA, which can save you a boatload on cooling costs.
There are products on the market designed for asphalt shingles that you simply spray or brush on to convert your traditional shingle roof into a cool roof, but these products may not be all they’re cracked up to be.
You can find these asphalt shingle coating products at most home improvement stores and many roofing contractors apply them as well. However, shingle manufacturers, such as GAF-ELK, do not recommend coating installed shingles with any product because it can potentially degrade its quality and shorten its lifespan. It can even void the shingle manufacturer’s warranty in some cases.
Utility Company Hit with Lawsuit over Cool Roof Coatings
Florida’s largest utility company, Florida Power & Light (FPL), was slammed with a class action lawsuit a few years back involving shingle coatings applied to more than 4,700 homes throughout the Miami area. Between 2007 and 2009, FPL offered consumers rebates for having the cool roof coating applied to their shingles. The idea was that by applying the coating, homeowners would use less energy cooling their home. That plan pretty much backfired.
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Homeowners soon complained of excessive roof leaks, curling/cupping shingles, and rotted shingles. The white-colored, reflective elastomeric coating used was obviously not suitable for asphalt shingle roofs. In fact, most shingles are not designed to handle any type of protective coating.
Not surprisingly, the National Roofing Contractors Association (NRCA) does not recommend any type of protective coating be applied to shingle roofs. This is true in warm parts of the country, such as Florida, and equally true in Northern U.S. states.
Cost of Cool Roofing Shingles is Negligible
The EPA points out that the cost of purchasing cool roofing shingles with reflective pigment already added is only about $0.10 per square foot more compared to traditional shingles. So, it would cost an additional $100 to $150 to install cool roofing shingles on the average home compared to traditional shingles. The long term energy savings will more than make up for the initial cost difference. Factory-coated cool roofing shingles don't suffer from the same quality issues that field-coated traditional shingles do, as shown in the Miami case.
Cool Roofing vs. Traditional Shingles – Energy Savings
A study in California examined the cost savings of cool roofing. It found that the average energy savings was about $0.50 per square foot. This figure factors in the steeper initial cost of cool roofing, increased heating costs during the winter months (the one potential downside of cool roofing), savings from downsizing AC cooling units, and several other factors. This study was done on commercial cool roofs, so the savings may be slightly different for residential steep-slope applications; however, the savings are still there nonetheless.
For the average 1,000 square foot residential roof, a yearly energy savings of $0.50 per square foot yields about $500 annually. Even if you achieved an energy savings of just 1/5 of that amount, you’d be looking at a savings of $2,000 over the life of the roof (assuming a 20-year lifespan). Add the federal tax credits available for cool roofing products you can cash in on, and the savings grow even further. The numbers make sense.
To Coat, or not to Coat?
New roofing products are entering the market all the time, each promising to deliver unsurpassed performance and cost savings. Many fall short of this claim and can even cause more damage than good, as was the case with FPL in Miami a few years ago. So, should you try the latest and greatest new shingle roofing protectant on the market?
The safest way to go is to avoid these types of products, but if you wish to give it whirl anyhow, be cautious. Check your shingle manufacturer’s warranty to see if these spray/brush-on products void your warranty. Read through the protectant product’s warranty as well to see if they cover damage to your roof in cases where the product fails. Some may require that a licensed roofing company apply the product. If your shingle roof is nearing the end of its usable lifespan – about 15 to 20 years -- consider upgrading to reflective coating shingles to benefit from the “hot” cool-roofing movement taking place in America as we speak.