Dishwashers using Hot Water

Supplying dishwashers with hot water greatly reduces their energy consumption.

A no-frills dishwasher with an Energy Star Rating of 2 and a Water Star Rating of 2.5 on a ‘Normal cycle’ uses 16 litres and:

• 0.971 kWh per load when supplying only cold water (20°C)
• 0.377 kWh per load when supplying hot water (60°C). 

At one load per day and a price of 30 cents per kWh, this equates to approximately 354 kWh costing $106 per year when supplying only cold water and only 137 kWh costing $41 when supplying hot water.

Obviously, the cost of heating the water externally has to be taken into account, but supplying hot water to dishwashers saves between half and two thirds of their electricity usage.