The paper presents a system for heat recovery from the domestic waste warm water from buildings with application for heating floors with bifilar coil. Although at a low temperature level, the recovered heat can be used directly for floor heating of some areas situated on the ground floor of the buildings, eventually an extra electric heater being provided for the secondary warm water (i.e. from the coil). The paper also describes a variant of accomplishing heating floor that leads to increase of its life span, by using bifilar coil. On taking into account the method of laying down the two pipes, there results more constructive variants, but in order to simplify the problem only the case of full slab type radiating floor was analyzed.