How much electricity does a dishwasher use? Enter your dishwasher's wattage, its hours of use per day and your electricity rate, then click Calculate to get your daily, monthly and yearly cost and total kWh consumption. Those same results also cover dishwasher power consumption. Also see how much electricity does an electric furnace use.
If your electric bill has crept up lately, you may be asking how much electricity does a dishwasher use and whether the machine in your kitchen deserves the blame. The short answer is that a typical load pulls between roughly 1.7 and 3.1 kWh once you count the hot water, which works out to about 29 to 54 cents for each cycle at a rate of 17.2 cents per kilowatt-hour. This guide breaks down the watts, the water, the cost and the settings that move the number, so you can judge your own household appliances with real figures instead of guesses.
Most full-size dishwashers are rated somewhere between 1,200 and 2,400 watts, and a commonly quoted average is about 1,800 watts. Compact and portable units can run on only a few hundred watts, while the most powerful models with built-in heaters can draw 2,500 watts or more. A watt is a rate of power, so the rating on its own does not tell you what you pay. What your utility bills you for is energy, measured in kilowatt-hours (kWh), and that depends on how long the machine actually draws power. For comparison, see desktop computer power consumption.
The relationship is simple, and you can apply it to any appliance in your home:
$$\text{kWh} = \frac{\text{watts} \times \text{hours of running time}}{1{,}000}$$
Then multiply the result by your electricity rate to get the cost of a single load:
$$\text{cost per load} = \text{kWh} \times \text{rate per kilowatt-hour}$$
The question of how many watts does a dishwasher use has two answers, because the machine does not draw its full rating for the whole cycle. The pump, the spray arm motor and the control electronics run for most of the program, while an internal heating element switches on only to boost water temperature or dry the load. That is why a nameplate reading of 1,500 watts can translate into well under 1.5 kWh for a two-hour program.
When the door is shut and nothing is running, a machine with a display still sips a few watts in standby. A steady 3-watt idle draw comes to about 26 kWh over 8,760 hours, which is under $5 a year at 17.2 cents, and a small fraction of the per-load use calculated below. It is part of your dishwasher's electricity bill, but rarely the part worth chasing.
Honestly, the machine itself does not use very much compared with the big household energy hogs such as a furnace, an air conditioner or a clothes dryer. The pump and control electronics need roughly the same power as a blow dryer or hairdryer running for a short time. The heavy lifting, literally, is the heat, and that heat usually comes from somewhere else in the house. Also see clothes dryer electricity consumption.
Three things decide where the electricity goes in any given load:
Because the last item is invisible on the machine, many people underestimate their true dishwasher energy consumption by a wide margin. A plug-in meter will show the first two, but your water heater bill carries the third.
Here is a complete calculation you can copy for your own kitchen. The scenario uses a dishwasher with a 1,500-watt rating that runs a two-hour program, but spends about 0.75 hours (45 minutes) of that time actually drawing the full rated power. Electricity costs 17.2 cents per kWh, and the household runs the machine five times a week, or about 21.7 loads a month and 260 loads a year.
The electric part of one load comes first:
$$\frac{1{,}500 \times 0.75}{1{,}000} = 1.125\ \text{kWh} \quad\Rightarrow\quad 1.125 \times \$0.172 = \$0.19$$
Next, add the energy your water heater spends to warm the incoming water. Heating one gallon of water by one degree Fahrenheit takes about 8.34 BTU, and one kWh equals 3,412 BTU. Assume the cold supply is 55 degrees and the tank delivers water at 120 degrees, a 65-degree rise, from an electric water heater that is 95 percent efficient:
$$\text{kWh}_{\text{water}} = \frac{\text{gallons} \times 8.34 \times 65}{3{,}412 \times 0.95}$$
The gallons per load matter enormously, and they depend mostly on when the machine was built. Machines made before 1994 can use 10 to 15 gallons of water per load, older ENERGY STAR units use 4 to 6 gallons, and current ENERGY STAR models use less than 4. The table runs three of those cases through the same formula:
| Dishwasher type | Gallons of water | Hot water kWh | Total kWh per load | Cost per load | Cost per month | Cost per year |
|---|---|---|---|---|---|---|
| Pre-1994 model | 12 | 2.007 | 3.132 | $0.54 | $11.67 | $140.06 |
| Older ENERGY STAR | 5.5 | 0.920 | 2.045 | $0.35 | $7.62 | $91.44 |
| Current ENERGY STAR | 3.4 | 0.569 | 1.694 | $0.29 | $6.31 | $75.74 |
Notice what the numbers reveal: in the oldest machine, the water heater accounts for about two thirds of the energy, while the motors and electronics stay constant at 1.125 kWh. Replacing that unit with a current ENERGY STAR model would save roughly $64 per year in this example, entirely by cutting the water volume.
The reason dishwashers get away with a modest wattage is that they piggyback on another appliance. As much as half of the energy tied to a load can come from the hot water heater, and that is true whether you heat water with electricity or natural gas. If your heater is an old tank unit with poor insulation, even a highly rated machine will cost more to run than the label suggests. A tankless water heater, which warms water only on demand, avoids standing losses, and wrapping a tank in an insulating jacket helps when it sits in an unheated garage or basement.
Your own water usage per cycle is printed in the manual and on the yellow EnergyGuide label, and it is the single best number for estimating the hot water share of your costs. If you are not sure how your machine compares, a quick test is to check the model number on the manufacturer's website.
Beyond the age of the machine, the program you pick changes electricity consumption noticeably. Longer cycles keep the pump running longer. Sanitize programs raise the water temperature, and a delicate setting lowers it. Heated drying can nearly double the electric cost of a load because it produces a second round of heat, while fan dry and air dry use far less. In the example above, adding a 0.45 kWh heated-dry stage would raise the 1.125 kWh electric portion to 1.575 kWh, an increase of about 40 percent.
Every new dishwasher sold in the United States carries a black and yellow EnergyGuide label with the estimated annual electricity use and the estimated yearly operating cost, shown for both an electric water heater and a natural gas water heater. The figures assume four loads a week and national average rates, so scale them up if your household runs the machine more often. To adjust, divide the label's yearly cost by 208 loads, then multiply by the number of loads you actually run. Compare with how many watts does a refrigerator use.
The ENERGY STAR logo goes a step further, marking a machine as energy efficient by federal standards, and it also caps how much water a single dishwasher cycle may use. A standard-size model earns it by using less than 270 kWh per year and no more than about 3.5 gallons of water per cycle, which puts it in the top tier of energy efficiency. When you compare two machines in a showroom, the one with the lower combined cost on the label is almost always the better long-term buy, even if the price tag is higher.
Electricity does not always cost the same every hour. If your plan has time of use pricing, the cost of a kilowatt-hour changes with demand, and rates are usually lowest at night when fewer people are drawing power. Most modern dishwashers include a delay-start option, so you can load the machine after dinner and let it run overnight, outside peak hours.
Running at night also moves the heat load of the water heater away from the hottest part of a summer afternoon, when the air conditioner is already working hard. As an illustration, if an off-peak rate of 10.9 cents replaces 17.2 cents, the 1.694 kWh load in the table drops from $0.29 to about $0.18, and a year of 260 loads falls from $75.74 to about $48.00. The machine and the number of loads stay the same; only the clock changes.
It feels counterintuitive, but the dishwasher is usually the lower-energy choice compared with handwashing. A modern machine can use up to nine times less water than washing the same dishes in the sink, and because most of the energy goes into heating water, using less water means using less energy. The result can be a wash at best if you hand wash with a lot of running hot water, and a clear loss for handwashing in most cases.
For perspective on energy usage across the home, the dishwasher sits well below the biggest consumers. Space heating, water heating and cooling dominate the typical household budget, with the refrigerator, the dryer and lighting making up much of the rest. The following comparison helps rank them:
A dishwasher usually adds only a few dollars to your monthly utility costs, which makes it a modest line item next to a refrigerator running all year or a dryer running most weekends. That is why the best payoff comes from fixing the biggest items first, and tuning your dishwasher habits second.
Buying an energy-efficient model is half the battle, and the other half is how you use it. These habits trim both the electric and the hot water portions of every load:
An upgrade is easiest to justify when your current machine predates the 1994 water standards or sits in the older models category that use around 6 gallons or more. Using the worked table, moving from a pre-1994 unit to a current ENERGY STAR dishwasher cuts the yearly figure from about $140 to about $76, a saving of roughly $64 a year before counting the water and sewer savings. Add in lower noise and better cleaning, and the upgrade case gets stronger. If your machine is under ten years old and runs on an eco setting, the payback on a new purchase is long enough that you will gain more by changing habits than by replacing the appliance.
You can estimate your own result in four steps, with nothing but your manual, your latest electricity statement and a calculator:
Those four steps tie your dishwasher's wattage and kWh per load directly to the dollar figure on your bill, so you can check any machine against the worked table above. Whatever you find, keep the scale in mind: for most homes the dishwasher costs between $6 and $12 a month to run, which is a small share of the average household bill. The habits that matter most are full loads, no heated drying and a sensible schedule, and each of them takes about a minute to change.