Possible cause: Insufficient attic ventilation causes heating/cooling
system to run excessively
In warm weather, inadequate ventilation will trap hot air in the attic,
causing air conditioning systems to work harder, or leaving your home’s
interior hotter and less comfortable. Attic Ventilation: In both hot and
cold weather, insufficient attic ventilation may cause moisture in the
attic to become trapped and condense on the rafters. This condensed
moisture can drip down onto the insulation and reduce its effectiveness.
Excessive energy costs can result.