TABLE OF CONTENTS The urban heat island effect is a phenomenon where daily temperatures are higher in urban areas than in the surrounding suburban and rural areas. It is thought to be caused by many factors some of which are an increase in paved and roofed surfaces that collect warmth from solar radiation, a decrease in foliage which can keep temperatures cooler by evapotranspiration, and an increased energy use in buildings that also warms the ambient air. This effect has many negative impacts including poorer air quality, an increase in energy demand for cooling, an increase in water demand, a reduction in building material durability, and an increase in human health concerns. Therefore, measures and construction practices which reduce the urban heat island effect are encouraged.
LEED-NC 2.2 lists the Intent, Requirements, and Potential Technologies and Strategies for this credit as follows:
Intent
Reduce heat islands (thermal gradient differences between developed and undeveloped areas) to minimize impact on microclimate and human and wildlife habitat.
Requirements
OPTION 1
Provide any combination of the following strategies for 50% of the site hardscape (including roads, sidewalks, courtyards and parking lots):
Shade (within 5 years of occupancy)
Paving materials with a Solar Reflectance Index (SRI) of at least 29
Open grid pavement system
OR
OPTION 2
Place a minimum of 50% of parking spaces under cover (defined as underground, under deck, under roof, or under a building). Any roof used...
