Building energy-efficient homes requires careful attention to insulation and sealing, especially in the attic. Unfortunately, this is an area that a lot of contractors and homeowners overlook when trying to make homes more sustainable. In the summer months, a properly insulated attic greatly reduces your air conditioning costs. The money you spend on the added insulation is easily recouped in as little as one season. This is because the insulation keeps the air around your air conditioning ducts cool, so they deliver colder air and the condenser does not have to work as hard.