Dishwashers actually use a surprising amount of Energy. That’s because the big by-product of a dishwasher is heat. And that’s not a good thing to have in your home in the middle of a hot summer because all that heat winds up adding to your home’s cooling load. To become a bit more savvy about energy and your dishwasher, let’s look more closely at their energy consumption and see why they’re more than just kitchen conveniences.
Do dishwashers use a lot of energy?
For dishwashers, energy usage is a two-pronged question. The first thing that consumes energy in a dishwasher is the machine’s pump and control electronics. Surprisingly, that’s not very much at all. An average dishwasher uses about 1200 watts; about the same as a blow dryer. With an average load run time of 1 hour, that becomes roughly 1.2 kWh or, assuming 10¢/kWh, 12¢. Let’s say you run a dishwasher load 5 days a week or 20 hours per month. You pay around $2.40 per month just for the appliance’s basic electricity consumption.
Dishwasher energy use per load
Remember that dishwashers not only have their own electrical demand but they also use hot water to clean the dishes. Unless yours has an onboard heater (which adds more to its energy consumption), most of the hot water used comes from your water heater. That means that the amount of hot water your dishwasher pulls through of your hot water heater will add to the machine’s total energy consumption per load. The more hot water the dishwasher uses, the more energy it uses. How much energy is that? It depends a lot on when it was made:
- Dishwashers dating from before 1994 can use 10 to 15 gallons of water per load.
- Older Energy Star dishwashers use 4 to 6 gallons of water per load.
- New standard-sized Energy Star dishwashers use less than 4 gallons.
How much does this hot water cost?
Assuming we’ve got an inlet temperature of 68°F and a target temperature of 120°F, we can estimate it like this:
- 1994 dishwasher using 10 gallons per load: 1.27 Kwh, or 12.7¢/hour. Add the average 12¢ cost to operate the machine’s electric components and the price becomes 24.7¢ total. At 20 loads per month= $4.94
- Older Energy Star dishwashers uses 5 gallons per load: 0.64 Kwh or 6.4¢/hour. Plus the 12¢ operating cost = 18.4¢. At 20 loads per month=$3.68
- New Energy Star dishwasher using 3.2 gallons per load: 0.38 Kwh or 3.8¢/hour. Plus the 12¢ operating cost = 15.8¢. At 20 loads per month= $3.16
—of course NONE of these include heated drying —which would essentially double the base electrical cost.
How much energy does a dishwasher use per cycle?
Wash cycles depend largely on the manufacturer’s design. For example, GE’s dishwashers have a variety of cycles, many of which depend on soil-level and whether the load is cookware, plates, glassware, etc. The energy consumption will depend on the amount of water used, the water pressure, and heated or unheated drying. Again, the more water and heat being used, the more energy the dishwasher will consume.
Interestingly enough, dishwashers are actually becoming the least used appliance in the US. According to EIA data for 2015,of 80 million households with a dishwasher, about 20% use them only once a week.
How to get the most out of your dishwasher:
- Only run your dishwasher when it has a full load but avoid over-loading. Water needs to circulate.
- Avoid using the heated dry. Hot water (150°) does a great job as a heat conductor. Hot dishes and glassware in a dishwasher actually act to evaporate water. Propping the door open as soon as the machine has finished washing will dry the load and use a lot less energy.
- Dishwashers need cleaning. Spray arms get clogged with soap scum, lime scale, and food particles. Filters get clogged. Newer dishwashers now come with a self-washing cycle.
Save even more energy by learning how much your other appliances use and by signing up for an electricity plan with Bounce Energy! We have great Texas electricity rates and plans so you can find the perfect electricity plan for your home.
