We are at an interesting juncture in our power and energy generation history. Not only are we to reduce our dependence on foreign sources of fuel and energy sources, but we must also develop inexpensive and indigenous sources of power and energy that are safe, reliable, and environmentally benign. In this paper, the physical measurements such as hot water heating supply temperature and pressure were carried out by using the equipped apparatus and numerous data loggers in real time over two years. In order to estimate the heating energy consumption, various measured data has been monitoring from mechanical rooms of apartment housings with district heating system in Il-san district, Kyung-gi province to data gathering place(University) in Seoul through the internet on the hourly basis. The actual heating supply temperature profiles(patterns) were analyzed which may be varied depending on ambient temperatures and distance. The purpose of this paper is to survey and analyze the effect of variation of heating transport distances from supplier to consumers(users) upon the supply temperature decrease in apartment housings with district heating system. It will establish the suitable design standards and suggest the basic databases for estimating heating energy demand.