Reducing Urban Heat Islands

Heat Island Reduction Activities cross the United States, a diverse group of stakeholders, from government agen- cies to corporations, have advanced urban heat island reduction strategies—urban Aforestry, green and cool roofs, and cool pavements—to lower summertime temperatures and achieve many energy and environmental benefits. Typically heat island mitigation is part of an energy, air quality, water, or sustainability effort,1 and activities range from voluntary initiatives, such as cool pavement demonstration projects, to policy actions, such as requiring cool roofs via building codes. Some communities have elected to imple- ment both voluntary and policy initiatives. These efforts can complement each other, and sometimes an initiative that begins as a voluntary activity becomes required over time. This chapter draws from the experience of many different groups and covers a range of initiatives to highlight a variety of urban heat island reduction activities around the coun- try. Examples for the following types of activities are included: t Demonstration projects t Incentive programs t Urban forestry programs t Weatherization t Outreach and education t Awards t Procurement t Resolutions t Tree and landscape ordinances t Comprehensive plans and design guidelines t Zoning codes t Green building standards t Building codes t Air quality standards. HEAT ISLAND REDUCTION ACTIVITIES – DRAFT 1 publicity needed to develop larger initiatives, promote new technologies and help Heat Island Mitigation get them to market, and sometimes even Strategies encourage local economic development. (See the “Stimulating Local Economies and For more information on heat island Businesses” textbox.) reduction strategies, see the corre- sponding chapters of this compendium: Communities have found heat island dem- “Trees and Vegetation,” “Green Roofs,” onstration projects to be most effective “Cool Roofs,” and “Cool Pavements.” when they: t Target high-visibility projects. Focus- 1. Voluntary Efforts ing efforts on a prominent building or site helps attract attention to heat island Most community strategies to reduce heat mitigation efforts. islands have relied on voluntary efforts, which can generally be grouped into the t Measure benefits. Highlighting antici- following categories: pated benefits and collecting data on actual impacts provides useful informa- t Demonstration projects tion for planning future activities. These benefits also illustrate to others the t Incentive programs reasons and means to act. t Urban forestry programs t Convey lessons learned. Documenting t Weatherization how demonstration projects are con- t Outreach and education ducted makes them easier to replicate t Awards. and improve. Many groups choose to conduct just one kind of activity; others combine ap- proaches. For example, some utilities have Lead By Example focused on cool roof rebates to encourage consumers to install reflective roofing prod- “Lead by example” programs involve ucts. Some local environment departments implementing strategies within lo- have sponsored demonstration projects, cal and state government facilities, conducted outreach and education efforts operations, and fleets, where appro- to publicize results, and have provided priate. These programs offer energy, grants to support use of mitigation tech- environmental, and financial benefits nologies by residents and industry. while creating an important opportu- nity for governments to demonstrate 1.1 Demonstration Projects the economic feasibility of the strate- Local governments, universities, and other gies they are promoting. This lead- organizations have used projects to demon- ership can raise public awareness strate a specific heat island mitigation strat- of the benefits of urban heat island egy and quantify its benefits in a controlled reduction strategies, which can lead environment. Documenting the project to increased public and private sector and its results can provide the data and support for advancing them. 2 REDUCING URBAN HEAT ISLANDS – DRAFT A variety of organizations can be the chief Figure 1: Chicago City Hall Green Roof agents of change and the first to test alter- native technologies, often in highly visible, public facilities. Demonstration projects have taken place in parks, schools, and mu- nicipal buildings like city hall. These projects often also monitor costs and benefits, such as energy savings. Examples include: t Chicago installed a green roof on its city hall that includes 20,000 plants, shrubs, grasses, vines, and trees. The Katrin Barth-Scholz/Department of Energy city expects to save directly more than Chicago’s commitment to green roofs includes 9,270 kilowatt-hours (kWh) per year of demonstration projects, such as on its City Hall, electricity and nearly 740 million British education, incentives, and policy actions. thermal units (Btu) per year of natural gas for heating. This energy savings translates into about $3,600 annually, and savings will increase with higher energy prices. In addition to assess- Stimulating Local ing energy impacts, the green roof has Economies and Businesses been designed to test different types of rooftop garden systems, success rates The non-profit group Sustainable of native and non-native vegetation, South Bronx has developed several and reductions in stormwater runoff. goals for the green roof/cool roof This city hall green roof has helped to demonstration project on top of its raise the visibility of green roofs and to office building in Hunts Point. These increase public understanding of them. goals include gathering research on Chicago’s Department of Environment local benefits, establishing a resource staff has frequently given presentations for the community, educating New about the roof, which has won numer- Yorkers on the value of green roofs, ous awards. For further information, go and advocating sustainable building to <http://egov.city ofchicago.org> and practices. The demonstration project look under the Department of Environ- has become a springboard for de- ment’s City Hall green roof project. veloping a local green and cool roof installation company to provide em- t A demonstration project for Tucson ployment opportunities in the South documented how a cool roof re- Bronx area. The group’s business is duced temperatures inside and on called SmartRoofs and includes a job- the roof of the building and saved training program for local residents. more than 400 million Btu annually See <www.ssbx.org/greenroofs. in energy. A white elastomeric coating html#> for more information. was installed over a 28,000-square foot (2,600 m2), unshaded metal roof on one of the city’s administration buildings. Following the installation, energy savings were calculated at 50 to 65 HEAT ISLAND REDUCTION ACTIVITIES – DRAFT 3 percent of the building’s cooling ener- with an eastern, western, or south- gy—an avoided energy cost of nearly ern exposure that heats up during the $4,000 annually. See <www.swenergy. summer are eligible for this program. org/casestudies/arizona/tucson_topsc. SMUD provides trees between four htm> for more information. and seven feet tall (1.2-2.2 m), as well as stakes, ties, fertilizer, tree delivery, 1.2 Incentives and expert advice on tree selection Incentives have proven to be an effective and planting techniques free of charge. way to spur individual heat island reduc- Homeowners must agree to plant and tion actions. Incentives from governments, care for the trees. See <www.smud.org/ utilities, and other organizations can in- residential/trees/index.html> for more clude below-market loans, tax breaks, information. SMUD also offers rebates product rebates, grants, and giveaways. For to residential customers who use cool example: roofing technologies. The utility offers a 20-cent-per-square-foot (0.09 m2) rebate t Since 2006, Baltimore County’s Grow- to customers who own single-family, ing Home Campaign has provided multi-family, or mobile homes with flat $10 coupons to homeowners toward roofs and who install ENERGY STAR® the purchase of most trees at local cool roof products. nurseries. Each coupon represents $5 of t Af ter the success of its green roof dem- public funds and $5 of retail funds. In onstration project, Chicago established order to validate their coupons, hom- green and cool roof grant programs. eowners provide information including The green roof program cites the ability tree type and location planted, which of green roofs to “create energy savings allows the county to integrate the data for building,” “lower surrounding urban with future tree canopy studies. The heat temperatures,” and “reduce storm county began the program as an in- water runoff, improve water quality, and novative way to increase tree canopy create conditions for longer-lasting roof cover as part of its larger “Green Re- systems.” Similarly, the city recognizes naissance” forest conservation and sus- cool roofs “not only help reduce cooling tainability plan. In the first two months costs, but can also have a positive envi- of the program, 1,700 trees were plant- ronmental impact by reducing the urban ed. See <http://fpum.org/pdf/MD%20 heat island effect.” In 2005, its first year, managing_forest_resources.pdf> and the program supported 20 green roof <www.baltimorecountymd.gov/Agen- installation projects; in 2006, it helped cies/environment/growinghome/index. fund 40. In the fall of 2007, the city an- html> for further information. nounced that it was expanding the pro- t Since 1990, the Sacramento Mu- gram to include cool roofs and

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