The test bed consists of two parallel closed air ducts in which a vertical measuring section has been integrated. They can either be controlled individually using a constant temperature together with a precisely defined air speed and a defined degree of turbulence, or they can be continuously changed according to a given pattern. A rapid shift of the air ducts in relation to the measuring section leads to step responses. Thermostatic radiator valves, controllers with or without valves as well sensors can be measured in the test facilities. The step responses of the actuating variables / sensor outputs are recorded by measuring the flow rate, temperature or electrical signals.