How to choose a power supply for a warm floor? If the area of the room, which needs to be heated less than 6 kV. m., You can not be afraid and include it in the existing power supply system, the system will not be overloaded. But if you need to heat a larger room, then when the additional devices are turned on with a capacity of more than 2000 watts, the appearance of problems in the form of stress surges is inevitable. That is why when using a large mat you need additional wiring, which has its own machine.