An imaging thermographic measuring system to measure the thermal output (Qout) at a target object, such as a building wall, building facade, or the like, comprising a measuring station provided for the arrangement distant from the object with an electric imaging device to record a thermographic thermal image, with a temperature distribution to be allocated thereto, and with a temperature sensor distant from the object to measure a temperature (Tref) distant from the object; at least one thermal transition sensor provided to be arrange close to the object, a transmission arrangement to transmit values between at least one thermal transition sensor and the measuring station, with the thermal transition sensor being embodied to predetermine the test values to determine a thermal transition coefficient (h).