While equilibrium is often thought of as a stable or inert state of a system, this kind of equilibrium rarely exists. More often, what seems to be a static state of a system is an equilibrium in a dynamic state among two or more entities where the inflows and outflows are essentially equivalent. A common example offered is a heating system attempting to heat a room to a given temperature. The temperature of the room is stable when the inflow of heat from the heating system is matching the outflow of heat loss to the surrounding environment.