RCU recuperative heaters are able to recover a high percentage of heat and energy contained in the foul air. This guarantees the necessary air change. The exchanger to the outer gains heat from the recycled air. When the air gets colder, it can then be pre-heated and then reduces the thermal shock in comparison to the interior temperature. In the summertime, high temperatures and humidity characterizes the outer air. With a recuperative heater, the outside air is pre-chilled when combining with an air-conditioning plant.