The purpose of this study is to evaluate for application of the new type of floor heating system with an improved performance than an existed floor heating system in apartment houses. The warmer and moderate part Ondol system suggested in this study were applied to the experimental apartment house and the mock-up room. The field measurements for this system were executed in winter climates. As a result of field measurement, when the load differences between perimeter zone and central zone are increased, the separately controled Ondol system divided in the warmer and moderate part can be evaluated as the new Ondol system with a capability for suppling proper heating energy for each zone. The user can have the freedom for changing warmer parts and the moderate parts and controlling each temperature according to their needs.