When Does Heat Transfer Stop?

Temperature Difference

The transfer of heat will continue as long as there is a difference in temperature between the two locations. Once the two locations have reached the same temperature, thermal equilibrium is established and the heat transfer stops.

At what point will the heat flow stop?

Heat flow stops when the two systems reach the same temperature. In other words, now the two systems are in thermal equilibrium with each other and there is no more heat flow taking place between the two systems.