These high attic temperatures

These high attic temperatures can lead to accelerated shingle distortion and deterioration.

These high attic temperatures also can lead to higher energy consumption: Typically, on a hot day, the upper rooms of a home are warmer because warm (lighter) air rises while cooler (denser) air falls. However, when improper attic ventilation allows the attic to become super-heated, the phenomenon of downward heat migration occurs (through the attic floor and into the home’s upper floors). This makes the upper floors of the home even warmer. The extra heating of the upper floors is not usually alleviated by the night time; an inadequately ventilated attic seldom loses enough heat overnight to compensate for the heat gained during the day. This effect is magnified in modern homes with heavier insulation that prevents heat from escaping from the upper floors. The extra heating of the upper floors due to the downward migration of heat causes homeowners to run mechanical equipment, such as air conditioners and window fans, longer than they otherwise would in order to cool down the home. In this way, inadequately ventilated attics contribute to greater energy consumption in higher utility bills during the summer.