Cool roofs are an effective alternative to bulk atticinsulation under roofs in humidtropical and subtropicalclimates. Bulk insulation can be entirely replaced by roofing systems that both reflect incident solar radiation and provide emission to the sky. Present technology is best obtained with white paint, but U.S. energy-star awards may soon be available for "cool colors" in addition to white painted roofs. Cool roof coatings function across a broader spectrum of solar radiation than white paint, especially in the infrared where the bulk of solar energy is presented. Highly emmissive and reflective cool roof painting systems are available in Australia for a material cost, epoxyprimer and highbuild coolroof, so this alternative solution should not be ignored in tropical northern Australia. A typical attic. ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... A roof tiled in imitation of thatch at Croyde, north Devon, England Rooftops in Vietnam Snow on the roof The roof, the top covering of a building, is one of the universal structures found on all buildings. ... Humidity is the quantity of moisture in the air. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ... Subtropical (or semitropical) areas are those adjacent to the tropics, usually roughly defined as the ranges 23. ... Solar irradiance spectrum at top of atmosphere. ... This article does not adequately cite its references or sources. ... A roof coating is a monolithic, fully adhered, fluid applied roofing membrane. ... Epoxy or polyepoxide is a thermosetting epoxide polymer that cures (polymerizes and crosslinks) when mixed with a catalyzing agent or hardener. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A. The first commercial attempts to prepare resins from epichlorohydrin occurred in 1927 in the United... Primer is a preparatory coating put on materials before painting. ...
Most of the roofs in the world (including over 90% of the roofs in the United States) are dark-colored. These low-reflectance surfaces reach temperatures of 150 to 190°F (66 to 88°C) and contribute to:
Increased cooling energy use and higher utility bills;
Higher peak electricity demand, raised electricity production costs, and a potentially overburdened power grid;
Reduced indoor comfort;
Increased air pollution due to the intensification of the "heat island effect"; and
Accelerated deterioration of roofing materials, increased roof maintenance costs, and high levels of roofing waste sent to landfills.
In contrast, cool roof systems with high reflectance and emittance stay up to 70°F (39°C) cooler than traditional materials during peak summer weather. Benefits of cool roofs include reduced building heat-gain and saving on summertime air conditioning expenditures. By minimizing energy use, cool roofs do more than save money – they reduce the demand for electric power and resulting air pollution and greenhouse gas emissions.
A reflective roof coating application can dramatically reduce roof surface temperatures. A roof coating is a monolithic, fully adhered, fluid applied roofing membrane. ...
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