We at Capital Home Builders do not install duck work in ATTIC. Other builders in Thomasville, and South Georgia do!
An attic is not ideal for heating and cooling ductwork. It is putting hot air where it’s coldest in winter, and cool air where it’s hottest in summer. This placement will put an extra load on the central unit, leading to higher utility bills and maintenance problems. But sometimes you cannot avoid it, such as in older houses or in additions or large spaces without room in walls for ducts. Several ways to mitigate the problem exist.
Design your attic ductwork carefully. Proper design is critical to make sure the system has enough air flow, is properly balanced and will not create hot or cold spots in the house. This planning involves calculating temperature differences between the attic and outside and the air flow required for the length of the attic ductwork, which will influence the size of duct used. Air Conditioning Contractors of America has a manual devoted to this issue. Try to install return ducts and air handler outside the attic. If they must be in the attic, put them in an enclosed and insulated space. Make sure filters are easily accessible for regular changing.
Insulate everything before you install attic ductwork. Start with the attic itself — make sure it has sufficient basic insulation. If there is any doubt, add more (preferably with insulating sheets). Use duct material that has extra insulation. If using metal ductwork, insulate it on all sides. If using flexduct, make sure it has more than the standard insulation used in basements and crawl spaces. Be certain all insulation is tight on the ducts and you have sealed all joints properly, with screws in metal, and metal or plastic bands on flexduct. Finish all sealing with a special duct sealant.
Test your attic ductwork for leaks. Air leaks are bad in ducts anywhere, but are especially critical in attics. You can use a blower to force air through the ducts to detect leaks or simply force your central unit’s fan to start. Watch for visible signs of leaks — material flapping or insulation blowing. Carefully check all joints and make sure there are no bends or twists that could affect air flow. You also can hire a professional to measure air flow to determine if the ductwork is losing air.