The U.S. Department of Energy (DOE) in late July announced a new policy to have all of its facilities outfitted with more energy-efficient "cool roofs" when it is cost-effective to do so. The policy is part of a series of initiatives under way at DOE facilities and buildings across the federal government.
Cool roofs use lighter-colored roofing surfaces or special coatings to reflect more of the sun's heat, helping improve building efficiency by reducing cooling costs and offsetting carbon emissions.
Under President Obama's Executive Order on Sustainability, the federal government has committed to reduce its greenhouse gas emissions 28 percent by 2020. As part of that effort, Energy Secretary Steven Chu directed all DOE offices to install cool roofs "whenever cost effective over the lifetime of the roof" when constructing new roofs or replacing old ones at DOE facilities.
Chu also issued a letter to the heads of other federal agencies, encouraging them to take similar steps at their facilities. To offer additional support for federal and commercial building operators that are looking to install cool roofs, DOE released its Guidelines for Selecting Cool Roofs, which provides technical assistance on types of roofing materials and how to select the roof that will work best on a specific facility.
Roofs and road pavement cover an estimated 50-65 percent of urban areas, according to DOE. "Because they absorb so much heat, dark-colored roofs and roadways create what is called the 'urban heat island effect,' where a city is significantly warmer than its surrounding rural areas. Cool roofs significantly reduce the heat island effect and improve air quality by reducing emissions. A recent study by researchers at Lawrence Berkeley National Laboratory found that using cool roofs and cool pavements in cities around the world can help reduce the demand for air conditioning, cool entire cities, and potentially cancel the heating effect of up to two years of worldwide carbon dioxide emissions."
DOE is also expanding its research activity for cool roofs to enable technological innovation and guide policy implementation. The research effort includes developing advanced testing protocols, conducting urban heat island analyses, and undertaking studies to further quantify the direct global cooling benefits associated with cool surfaces. The department also anticipates awarding new projects to develop higher performing, new innovative roofing materials under its Small Business Innovation Research grant program.
DOE Spokesperson Goes Into Further Detail About Cool Roofs in an Interview with GBI
In an interview with Green Building Insider, DOE spokesperson Chris Kielich provided the following additional details about the agency's plans for cool roofs:
GBI: DOE intends to install a cool roof whenever cost-effective over the roof's lifetime. What does DOE consider cost-effective? Does that mean that the savings from reduced electricity bills would have to exceed the cool roof's initial cost premium by a certain year?
Kielich: That is a good way of thinking about it. The lifetime of a roof is approximately 20 years, so the cost savings (on energy bills) gleaned from a more-efficient, cool roof would have to offset any cost premium associated with the roof within about 20 years for it to be cost effective. This is generally achievable with current cool roof technologies. In fact, cool roofs don't always cost more than traditional roofs, but they immediately lower the building's energy demand.
The Federal Energy Management Program website has a wealth of information on cool roofs, including the recently published Building Technologies Program "buying guide." It's at the top of the cool roof resources, click here.
Cost calculations vary by climate, roof type, exposure, etc. Page 10 of this PDF: click here, discusses the cost issue in depth. We are currently examining specific ways to ensure that cost-effective cool roofs are installed whenever possible on our facilities.
More generally, a flat roof is cost neutral -- if it is going to be replaced, it costs the same to do a white roof as it would to do a dark roof. Sloped roofs can be more expensive, but there are tax credits available for consumers. Also, we have a calculator at http://www.roofcalc.com/ that can help determine the cost effectiveness of a cool roof.
GBI: About how much money is available or will be available for this component of DOE's overall cool roof strategy? About how much more does it cost to install a typical cool roof instead of a traditional roof?
Kielich: There will not be a 'cool roof' specific budget line, but rather cool roofs will become part and parcel of all routine expenditures on new construction and major retrofits. Page 10 of the following PDF: http://www1.eere.energy.gov/femp/pdfs/coolroofguide.pdf -- discusses the cost issue in depth.
GBI: Approximately how many DOE facilities and/or what percentage of all DOE facilities are expected to receive a cool roof under this initiative? About what percentage/number of DOE facilities have been receiving cool roofs?
Kielich: DOE expects to equip nearly all of its facilities with cool roofs in future construction and major reconstruction going forward, but there is not going to be a major effort to tear up roofs that are in working order and replace them with cool roofs. That wouldn't be cost effective. Roofs typically need replacement every 20 years.
GBI: To which other agencies did Secretary Chu send his letter to recommend comparable initiatives? From which other agencies did he receive a response, and what did those responses say?
Kielich: Secretary Chu's memo went out to all federal agencies. As there have only been a few days since Dr. Chu's letter, we expect to receive replies from the agencies in the coming months.
GBI: Regarding cool roof research, what is the expected timetable for finishing that research? How much money is available for DOE's cool roof research program?
Kielich: The research budget for fiscal 2010 is around $1 million. That may increase to between $2.5 million and $3.5 million next year. We will be developing a roadmap for cool roof research this fall (a draft should be ready in late September), which will cover the next few years of work for us. Currently, there is no discussion of DOE being finished with this research -- there is still a lot to be done.
