The Energy Star rating criteria for undercounter warewashers has been recently updated. 

With the new Energy Star standards, high-temp undercounter warewashers are required to have idle energy rates of less than 0.50 kW and water consumption of less than .86 gallons per rack. For low-temp Energy Star machines, the idle energy rate is less than .50 kW and water consumption is less than 1.19 gallons per rack.

Those looking to save money and energy should consider an undercounter warewasher that incorporates a built-in thermostat. With these units, the temperature is regulated and heat is only turned on when needed.