The actual energy performance of buildings depends on not only the design criteria but also on the construction quality of buildings. Many design assumptions can be invalidated by unexpected construction quality issues, and lead to large variations between the designed performance and the constructed performance. Though important, very limited research, especially quantitative study, is found on evaluating the impact of construction quality issues on building energy performance. In this paper the construction quality issues of residential buildings in the United States is discussed, along with reviews of building envelope related research. A case study on residential attic construction is presented to illustrate how construction quality affects the energy performance of attics. The case study utilized 3D computational fluid dynamics to simulate air leakage issues in recessed lighting using different boundary conditions. The results of the case study suggest that some seemingly insignificant construction quality issue can cause significant increase in energy consumption of residential buildings. The paper provides scientific evidence to help residential construction industry to improve the construction quality of residential buildings in the United States.