Modular heating or air conditioning device

The heating or conditioning system, especially for a motor vehicle, can accommodate an additional heater element which in the modified system can be a non-heatable substitute element (5). The substitute element has the same outside dimensions as the heater element it is replacing. The substitute element is formed by a guide vane grid which has profiled and adjusted vanes which can be arranged in the horizontally and/or vertical direction. Independent claims are also included for the following: (a) a heating or conditioning module which may include a non-heatable substitute element; and (b) a substitute element for use in a heating or conditioning system.