Abstract: A compressed air installation having a normal operating mode and an idling mode includes a feed valve, a feed line which is connected to and receives air through the feed valve, at least one compressor having at least one compression chamber, and at least one inlet valve which is connected to the feed line and supplies air to the compression chamber. The feed valve and the inlet valve are switchable between open positions and one-way positions wherein air can pass through the valve in one direction only. In normal operating mode, the feed valve is in its open position and the inlet valve is in its one-way position, thereby allowing air to enter and exit the installation through the feed valve and the feed line, and to pass from the feed line through the inlet valve into the compression chamber.