The Department of Energy tells us you can reduce your heating and cooling needs by 30 percent just by adding a few hundred bucks' worth of new insulation. This is especially true if your house is more than 25 years old, from the time before building codes became more mindful of energy efficiency, and you haven't added any new batts yet. We tend to focus on the attic, but it's also wise to see how much insulation you have in crawl spaces, ceilings, basement walls, and around recessed lighting fixtures (just make sure those fixtures are designed for direct insulation contact). Check that your R-value is right for the climate where you live. In general, R-values should run between R-22 and R-49 in the attic, less in other spots. Learn how to properly insulate your attic
from This Old House
general contractor Tom Silva.