We present the household electricity use for air conditioning in the residential sector in Hong Kong during the 26 year period from 1971 to 1996. Air conditioning accounts for about one third of the total electricity use in the residential sector. A survey of the existing residential buildings has been conducted to establish typical design features. Based on these typical design variables, we use computer simulation techniques to estimate the likely energy savings from two energy efficient measures - the use of tinted glass to reduce solar heat and the application of thermal insulation to the external walls to lower heat conduction. The building energy computer program DOE-2 was used to predict the electricity savings for the 11 year period from 1997 to 2007. It has been found that the electricity savings are small during the initial years, about 0.2% of the total electricity use in the residential sector in 1997. However, as older buildings are replaced by newer ones with more energy efficient design features, the energy savings in subsequent years will have a bigger impact on the overall electricity use situation in the residential sector.