A well insulated home is a critical part of overall home energy efficiency. This starts with the attic. Adequate attic insulation is certain to be a major target in terms of energy-saving improvements. Here's why: In a typical house, almost 50% of total energy use is attributable to heating and cooling, and the attic has a HUGE impact on heating and cooling efficiency. Over half of a homes energy loss is through the attic, walls, and floors.