This paper shows that the price of the kilo Watt hour can be used to level off daily peak demands of heat energy in district heating without compromising the end customer’s comfort. A 5 days simulation of a building at an outdoor temperature of -15°C shows a 20% power consumption reduction causing only a 1°C variation of indoor temperature when the price is raised as a function of heat energy demand. This control scheme is made possible when using Internet communication between the heat supplier and the buildings’ substation when the latter is equipped with a wireless sensor network to share internal information.