A warewasher for washing wares includes a housing defining an internal space with at least one spray zone for washing wares. A liquid delivery system provides a spray of liquid within the spray zone. A tank includes an inlet that is connected to a hot water source for filling the tank with hot water. The liquid delivery system receives water from the tank. An exhaust vents heated air from the housing. A final rinse system is connected to a cold water source. A heat recovery system is located between the final rinse system and the cold water source. The heat recovery system transfers heat from the exhaust air to the cold water provided from the cold water source. A valve associated with the hot water source selectively supplements the water exiting the heat recovery system with hot water from the hot water source.