Again the Duct Work

In houses with forced-air heating and cooling systems, ducts are used to distribute conditioned air throughout the house. In a typical house, however, about 20 percent of the air that moves through the duct system is lost due to leaks and poorly sealed connections. The result is higher utility bills and difficulty keeping the house comfortable, no matter how the thermostat is set.
Because some ducts are concealed in walls and between floors, repairing them can be difficult.

However, exposed ducts in attics, basements, crawlspaces, and garages can be repaired by sealing the leaks with duct sealant (also called duct mastic). In addition, insulating ducts that run through spaces that get hot in summer or cold in winter (like attics, garages, or crawlspaces) can save significant energy.

Additionally, if you are replacing your forced-air heating and cooling equipment, make sure your contractor installs the new system according to ENERGY STAR quality installation guidelines. A quality installation will include a thorough inspection of your duct system, including proper sealing and balancing of ductwork, to help ensure that your new system delivers the most comfort and efficiency.

Learn more about improving your ducts.