Provided is a method for measuring the temperature at each location of a pipe in a hot water supply system comprising a water heater, a pipe, and outlets, the method comprising checking for a temperature of a first point (TP1), which is upstream of the outlet, a temperature of a second point (TP2), which is downstream of the outlet and an outdoor temperature (TA), and confirming a length (L) of the pipe from the first point to the second point, then measuring a temperature of the pipe located at a distance of x away from the first point.