New homes are tightly built to save energy. An unventilated – or inadequately ventilated attic seldom loses enough heat overnight to compensate for the heat gained during the day. Eventually, this accumulation of heat begins to have more practical – and costly – consequences. The most obvious are the actions taken by homeowners to cool themselves. To reduce the effect of the heat – not only the daytime heat gain but also the excess heat being stored in the attic – they turn on fans, window air conditioners or central air conditioning systems. As the hot weather continues, these appliances run longer and longer – a fact well documented by utility companies across the country. Homeowners pay for all this added energy consumption in higher utility bills. A less obvious – but equally costly – consequence can be found on the roof itself. Homeowners can’t see it happening, but over time excess attic heat can cause some shingles to distort and deteriorate. The result is premature failure of roofing materials – and perhaps a leaky roof. Once that happens, the cost of a new roof is the least homeowners can expect to pay. More than likely, they also may face added costs for structural and interior repairs related to water infiltration.