The heat exchanger in the dishwasher allows the heat generated during the wash cycle to be used efficiently. This technology works by capturing the heat from the water used in the previous stages of the wash cycle and using it to pre-heat the water for the next stages of the cycle. This can lead to significant energy savings as the dishwasher does not need to use external heat sources as much to heat the water. The heat exchanger also protects the dishes from rapid temperature changes, which is particularly important for fragile items such as glass and porcelain that can be damaged by these temperature changes.