Recently, it is most important and fundamental factor for energy conservation to use insulated walls effectively in thermal design of building. The main purpose of this study is to investigate the effects of insulation position on the peak space heating load. In part 1, the results of analysis by daily periodical steady state calculations used heating design weather data, is described. The results are summerrized as follows : (1) In the three typical insulated model spaces, that is, moddel A which has inside-out insulated walls, model B which has outside-in insulated walls and model C which has inside-out insulated walls and insulated floor, the peak space loads became larger in the order model B,A,C (C is largest). This insulated floor is in place of insulated inner walls and insulated columns and floor covered with a carpet. (2) On the other hand, night space temperature became higher in the order model C,A,B. (3) There is little difference in operative temperatures among several types of insulated model spaces. (4) To shorter the time for air coditioning, the peak load in model B became largest of the three. (5) The effect of furniture on the peak space loads is significant. The thermal capacity of furniture causes increase of the peak space loads and the thermal capacity of walls and floors causes increase of the daily total space loads. (6) The daily total space load in model B is useally largest of the three models in each of various design parameters.