How does the AUTOTHERM ERS system work?

When a vehicle is driven, only 40 to 60% of the energy available from the fuel is used to propel the vehicle.
The rest of the energy is lost as waste heat and transferred to the water surrounding the engine and dissipated to the outside air by the vehicle radiator.

In winter, this hot water is circulated by the engine pump to the cabin heater to keep the passenger compartment warm.

This engine coolant contains a large amount of latent energy that is available to the cabin heater as long as the engine pump keeps running and circulating it to the heater.

As soon as the engine is turned off, circulation stops and the heater begins to rapidly cool blowing cold air in a few minutes. Using a small magnetically coupled pump, the AUTOTHERM system continues circulation of hot engine coolant to the heater when the engine is off, operates the heater fan and effectively continues vehicle interior heating with the engine off.
This is thousands of times more energy efficient than idling.