Cool Roof Glossary
Albedo
Another term for solar reflectance. See solar reflectance for definition.
Contractors State License Board (CSLB)
A state government agency that provides free publications about hiring contractors and the construction process. The CSLB licenses and regulates contractors in 43 license classifications, investigates complaints against contractors, and through SWIFT (Statewide Investigative Fraud Team), works to eliminate the number of unlicensed contractors working in California.
Cool Roof
Cool roofs are a highly reflective and emissive material that stays 50 to 60 degrees Fahrenheit cooler in the summer sun, thereby reducing energy costs, improving occupant comfort, cutting maintenance costs, increasing the life cycle of the roof, and contributing to the reduction of urban heat islands and associated smog.
Evaporative Cooler
Another term for swamp cooler. See swamp cooler for definition.
Flat Roof
Flat roofs generally have a small degree of pitch to them so that water will run off to a drain system and not pond. Thus "flat" roofs are low slope roofs.
Heat Island
Heat island refers to urban air and surface temperatures that are higher than nearby rural areas. Many U.S. cities and suburbs have air temperatures up to 10°F (5.6°C) warmer than the surrounding natural land cover.
Low Slope Roof
A "low-slope roof" is a roof surface with a maximum slope of 2 inches "rise" for 12 inches "run" as defined in American Society for Testing and Materials Standard E 1918-97.
Steep Slope Roof
Steep-slope roofs, or sloped roofs, are roof surfaces with a slope greater than 2 inches "rise" for 12 inches "run."
Solar Reflectance
Solar reflectance is a measure of the ability of a surface material to reflect sunlight - including the visible, infrared, and ultraviolet wavelengths - on a scale of 0 to 1. Solar reflectance is also called "albedo."
Swamp Cooler
Swamp coolers (also called evaporative coolers, air coolers, or desert coolers) are a type of refrigeration system which uses simple evaporation as the cooling mechanism. This differs from traditional air conditioning, which uses a phase change heat pump with a compressor. Evaporative cooling is especially well suited for climates where the air is hot and humidity is low. In such areas, the installation and operating cost of a swamp cooler can be much lower than traditional air conditioning.
In higher humidity areas, there are many proven cost-effective uses for evaporative cooling that make it the preferred choice. For example, industrial plants, commercial kitchens, laundries, dry cleaners, greenhouses, spot cooling (loading docks, warehouses, factories, construction sites, athletic events, workshops, garages, and kennels) and confinement farming (poultry ranches, hog, and dairy).
Thermal Emittance
The Thermal Emittance of a material refers to its ability to release absorbed heat. Scientists use a number between 0 and 1, or 0% and 100%, to express Emittance. With the exception of metals, most construction materials have emittance above 0.80.
Urban Heat Island
An urban heat island (UHI) is a metropolitan area which is significantly warmer than its surroundings. As population centers grow in size from village to town to city, they tend to have a corresponding increase in average temperature, which is more often welcome in winter months than in summertime. The EPA says: "On hot summer days, urban air can be 2-10°F [2-6°C] hotter than the surrounding countryside. Not to be confused with global warming, scientists call this phenomenon the 'urban heat island effect" [1].
