Most homeowners don't realize the heating & cooling that is being lost through the roof of their attics.
About 78% of homeowners have not added any insulation to their attic because they believe their home is adequately insulated.
However 80% of homes built before 1980 were not insulated to government standards. Even newer homes may not be as energy-efficient as you think.

State energy codes are only the minimum insulation requirements for new construction–not the amount recommended to optimize energy efficiency.
Overall, about 60 million homes in the U.S. are under-insulated costing Americans $8.2 billion each year. Simply insulating existing homes to current standards would save 800 trillion BTUs (that's 76 supertankers of oil) each year.

An energy-efficient home appeals to home buyers financial and environmental interests.
Research shows that 71% of homebuyers want a home that reduces their overall impact on the environment and 96% of home buyers consider energy efficiency when buying a new home.