This news item expired on Tuesday, December 31, 2013 so the information below could be outdated or incorrect.
If you have your air conditioning cranked up and you are still feeling hot, it may be your ducts are not sealed and some of the cold air is escaping prior to getting to the intended room. 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.
For more information, view this brochure on sealing ducts or call Buncombe County Cooperative Extension at 255-5522.
Source: www.energystar.gov