How to Choose the Best Roof Color: What Are the “Green” Facts?
So how do you choose colors for your roofing project?
Do you go White, Black, and how concerned are you with being “Green?” Are you more concerned about how long it lasts, the price, or the environment?
So- let’s learn about what color works for roofing in the Northwest…from a roofer:
Sharp Roofing will discuss roofing product greenness; we can even make educated suggestions. But this Seattle roofing company will not make blanket recommendations on supposed “green” products or “Cool Roofs.”
For many years there have been discussions, arguments, claims, half-truths, outright lies, etc. about what is really GREEN and friendly to the environment. There are organizations that monitor greenness.
One of these, TerraChoice, found that “More than 95% of products claiming to be green were found to commit AT LEAST ONE of the “Sins of Greenwashing” Cliff, from Sharp Roofing first became involved with green in roofing when the Master Builders Association of King and Snohomish Counties (MBA) “in partnership with King County and Snohomish counties, established Built Green® to provide consumers with an easy-to-understand rating system that quantifies environmentally friendly building practices.”
At that time the MBA came up with lots of “great” ideas.
As I recall for roofing their recommendations were:
- Cement fiber shakes. The fiber (I should say fibre as they were made in Canada) was recycled cardboard and paper bags. What a great idea! Cement, heavy and porous combined with cellulose. These were already starting to fail at the time the MBA recommended them. The final outcome was a class action suit and the manufacturer filed bankruptcy.
- 40-year warranty asphalt composition
- 30-year warranty asphalt composition
- 25-year warranty asphalt composition.
This made Cliff wonder…in the beautiful but damp Pacific Northwest, asphalt composition lasts an average of 20 years; the average nationally was much lower.
The longer the warranty period the more oil and other products used. They all last the same amount of time; so how is a product that uses more of our precious resources “greener” than one that does not.
Is Black Roofing Best?
Another “fact” promoted for quite some time is that white or light colored roofs are greener than dark ones. Now scientists are questioning this long established “fact.” It seems that in the northern half of the United States BLACK IS BEST! The logic is simple:
If you use air conditioning more than ½ the year, then the lighter the better with bright white being the best.
If you turn on your heat during most of the year, then the darker the better with flat black being the best.
Now, even though our roof consultants know a fair amount about roofing; Sharp Roofing did not come up with this information on our own.
Get in touch with Cliff or any of us at Sharp Roofing so you make the best roofing choice. Because there are plenty of roofing companies who might not guide you the best way.
We include a couple of articles that include the findings:
- “The High Cost of White Roofs in the North” printed in The Huffington Post
- “Special Feature: Reflective Roofs” printed in Today’s Facility Manager
The High Cost of White Roofs in the North
Charlie Soffel Northwest regional manager, Carlisle SynTec Posted: 07/28/2014 2:27 pm EDT Updated: 07/28/2014 2:59 pm EDT Summer is when new roofs are installed and old ones are redone, but contrary to news articles and experts touting the benefits of white reflective roofs, the fact is that my home city of Seattle and most northern cities in the U.S. waste millions in energy costs and precious natural resources by buying into the myth that white roofs are energy efficient regardless of climate zone. White roofs have been migrating north for the past 10 years.
There are mandates for their use in Chicago, New York and Philadelphia. I work for the leading manufacturer of both white and darker colored roofs, and we know that white roofs reduce cooling costs, which are beneficial in warmer, southern climates, but we also know the untold story is that they carry a significant heating penalty in cities like Seattle, where heating is utilized far more than cooling. Those with a vested interest in white roofing have capitalized on perceptions created by the Department of Energy’s ENERGY STAR program and incomplete studies from sources such as Lawrence Berkeley National Laboratory, and they have been able to launch a movement that not only is costly but also damaging to our environment. Using a roof energy savings calculator developed by Oak Ridge National Laboratory and approved by Lawrence Berkeley, the EPA, DOE and California Energy Commission, I found that regardless of heat source, square footage or insulation level, reflective white residential roofs in Seattle waste natural resources and cost homeowners more money.
The same is true with Seattle’s commercial buildings. A relatively small 10,000-square-foot building with a white roof and an insulation level of R-20 would have an average cooling benefit of $61, but would have an average heating penalty of $498, for a net energy cost loss of $437 per year.
Proponents also claim that white roofs reduce global warming. But a study http://news.stanford.edu/news/ 2011/ october/ur ban-heat-islands-101911.html at Stanford University shows that white roofs may actually INCREASE, not decrease, the earth’s temperature. The study suggests that white roofs reflect heat upward into the atmosphere where it mixes with black and brown soot particles that retain heat and contribute to global warming. Another study http://ncesmart.asu.edu/docs/ smart/unintended-consequences-1013.pdf from Arizona State University indicates widespread adoption of highly reflective cool roofs could negatively impact rainfall patterns across the United States.
Those northern cities that have adopted white roofing mandates, as well-intentioned as they may be, are beginning to get a black eye. Design professionals, roof consultants, contractors, facility managers and building scientists are getting increasingly concerned with mandates that limit their ability to choose the most energy-efficient roofing materials. They know it is a far more complex issue than just the roof’s color. The good news is that there is a growing resentment regarding these top-down, one-size-fits-all government mandates. The EPA is on record urging us to remember that “the energy savings that can be achieved with white reflective roofing is highly dependent on facility design, insulation used, climatic conditions, building location, and building envelope efficiency.” In the past year, three different national regulatory bodies voted down proposals to specify white reflective roofs in northern areas of the United States.
And in my region, recent building guides in the Pacific Northwest show that white roof installation is not recommended to improve energy efficiency when retrofitting a roof. So we are starting to expose the myth, but we must continue to research the issue and seek the facts to find balance and counter a movement that has built momentum over the last decade — and cost Seattle and other American cities untold dollars in unnecessary energy costs.
Here’s a great article at TodaysFacilityManager.com
Special Feature: Reflective Roofs
Posted on: August 13th, 2014 By David Pierce, RRO From the July/August 2014 issue of Today’s Facility Manager Photos: (left) NationalCoatings.com; (right) CommercialRoof.com.
For nearly two decades, the U.S Environmental Protection Agency’s (EPA) ENERGY STAR® program has labeled white roofing materials as an energy efficient means to reduce cooling costs through solar reflectance. As a result, the use of white roofing materials has proliferated in a variety of climate zones across the United States, but are these materials delivering on their energy efficient promise? Does it make sense to label one component of a roofing system “energy efficient” when a complete system design is required for true energy efficiency? Some experts say no, as new studies reveal efficiency losses and other complications for white roof applications, especially in northern climates where heating costs far outweigh cooling costs. The test of time for white roofing is producing mixed results; energy efficient roof color is vastly dependent upon climate, building use, energy costs, and roof system design.
It’s a fact. White roofs can save cooling costs. During the cooling season, white roofing materials reflect ultraviolet and infrared radiation in the form of heat away from a building, requiring less energy expenditure to cool the building. In Miami, for instance, the loss of reflected heat from a white roofing surface during the heating season is minimal and is easily outweighed by the savings gained from reflected heat during the cooling season. When accounting for both cooling and heating demands, white roofing material is a logical choice in a hot climate and location like Florida. But what effect does white roofing material have on energy efficiency during the cooling and heating seasons in cold, northern climates?
A Black And White Issue Travel north to Boston and the climate and location tell a different story for white roofs. There, the length of the cooling season is significantly shorter and the heating season is significantly longer than in Florida. A white roof installation in Boston would provide small cooling efficiencies during the cooling months and large losses in heating efficiency during the heating months. A white roof would reflect heat away from the building year round, causing an increase in heating costs and a net increase in energy demand over the course of the year. With white roof materials, energy costs in northern climates can actually increase—a fact not clearly reflected in the ENERGY STAR labels on reflective roofing materials.
According to the U.S. Department of Energy (DOE) Buildings Energy Data Book1, heating costs in northern climates are typically three to five times greater than cooling costs. ENERGY STAR recommends using the DOE’s Roof Savings Calculator2, to determine the net annual impact of white roofing material on both heating and cooling costs before assuming a white roof will save energy costs. Using this calculator, a cost comparison table (seen above) was created that shows black versus white roofing materials for the 25 most populated U.S. cities in colder climate zones. The sample data for a fairly common building design demonstrate the net annual impact in energy costs where R-20 insulation and gas heat are assumed for a one story, 10,000 square foot building; with a 40% window-to-wall ratio, post-1990 construction, and mid-efficiency heating and cooling equipment. A review of the calculations affirms why the distinction between heating and cooling demands must be considered. Using these specifications, the comparison shows a northern climate and location such as Boston would experience a $173 savings in cooling costs where white roofing is used, and incur a $673 heating penalty due to reflected heat during the heating season.
The net result is $500 in additional energy expenditures with white roofing material. Thus, the energy efficient color for Boston is black. Perhaps the most surprising city in this comparison is Nashville, TN. It might be assumed that a southern location would naturally dictate use of white roofing material, but even locations this far south can benefit from black roofing. The net annual impact is much smaller, $134, but nonetheless still demonstrates a building in Nashville would experience greater overall efficiency from a dark or black roof than from a white roof in this scenario. In order to select the best roofing materials, facility managers must consider components that meet the needs of building design, location, and climate conditions. And the industry could benefit from a re-examination of ENERGY STAR’s labeling practices; at a minimum, ENERGY STAR could include the same clarifications that can be found on its website.
The site refers users to the DOE’s Roof Savings Calculator and also states: “Please remember the energy savings that can be achieved with reflective roofing is highly dependent on facility design, insulation used, climatic conditions, building location, and building envelope efficiency.” Most importantly, ENERGY STAR could drop the single component approach altogether. The program excels in the appliance industry because the EPA evaluates a finished product. Likewise, a roof should be evaluated by the sum of its parts, not by a single component, as many components factor into an efficient and effective roof assembly. Pierce is the owner and President of Foothills Roof Services, Inc. in Larkspur, CO and has been involved in the roofing industry since 1980. He has been a member of the Roof Consultants Institute (RCI) since 1996, from which he earned his RRO certification in 1999. References: 1 Buildings Energy Data Book. (n.d.) Buildings Energy Data Book. Retrieved December 9, 2013, from http://buildingsdatabook.eren.doe.gov/ 2 Roof Savings Calculator (RSC) – DOE ORNL LBNL CEC EPA. (n.d.). Roof Savings Calculator (RSC) – DOE ORNL LBNL CEC EPA. Retrieved December 9, 2013, from http://rsc.ornl.gov/