What about that ductwork in your crawl space, or in the attic? It’s highly probable you haven’t considered it’s impact on your home’s energy efficiency. However, to quote Energy Star:
“In houses with forced-air heating and cooling systems, ducts are used to distribute conditioned air throughout the house. In a typical house… about 20 to 30 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts. The result is higher utility bills and difficulty keeping the house comfortable, no matter how the thermostat is set.”
Ductwork from the 80’s and 90’s was no higher than R-4.2 value. Modern ductwork is R-8.0, almost double. The result is significant energy and comfort gains, particularly for attic applications. In the summer months (especially in the South), attics can reach 130-140 degrees Fahrenheit. Imagine conditioned air circulating through this extremely hot space and the temperature of the air will increase significantly before it can get into your home. The better the duct insulation value, the colder this air will be, maximizing it’s ability to efficiently condition your home.
Craig Sopo 