A new floor heating system that the most part of the circulation pipe was substituted with a midair pipe made of copper was developed. The advantage of this system is 1) shortening of the construction period, 2) shortening of the pipe diameter and 3) the reduction of the load which hangs on boiler. Firstly, to examine the heating performance and the operation optimum condition, the comparison of the radiation performance was done by using the flux for parameter. Secondly, the comparison of heating performance of standard circulation-type system and the new system was done. As the results, about the flux, it found that 2.5 l/min was effective in case of this system and it became clear that the heating performance of new system was equal to the standard system which is in the market.