This paper describes thermal characteristics of a water flow type floor heating system using heat pumps. An experimental system is constructed in an environmental test room. It has a heating room with a floor area of 11.58 m2 and a heat loss coefficient of 2.35 W/(m2·K). The heat balance in the experimental system is observed. Higher efficiency of space heating can be seen at cases using floor heating panels with a thinner top layer and lower thermal resistance materials. These panels also show adaptive room temperatures above 20°C even at a lower water temperature about 30°C. The result reveals that such system may be a possible solution to provide energy saving as well as thermal comfort by the use of heat pumps.
