The Stack Effect
In an attic, evidence of air leakage and “stack effect” energy loss can often be found on the insulation installed directly on top of the attic floor. Insulation installed near an air leak often discolors from dust deposited on the fine fibers traveling in rising air. The comfort problems caused by the stack effect can also cause costly energy problems. With heated air leaving the house and cold air entering during the winter and reverse during the summer, the home’s heating/cooling system has to work longer and harder to maintain comfortable interior temperatures.
Out of the three drivers of the stack effect, height of the total living space, interior-exterior temperature difference, and amount of air leakage within the attic, it is only necessary for pest management professionals to focus on the amount of air leakage in the house as there is nothing to be done regarding the other two drivers. Air sealing the attic will effectively short-circuit the stack effect by dramatically reducing air exfiltration and infiltration. According to the U.S. DOE, attic sealing, when combined with and attic insulation upgrade, can cut annual heating/cooling costs nearly in half.