Dishwasher Cost Calculator

What a dishwasher load costs

A dishwasher has two running costs: the electricity that powers the pump and heats the water, and the water itself. Both are small per load, which is why the dishwasher looks cheap month to month and adds up over a year.

Here are the inputs that decide the number.

• Energy per load: most full-size models use 1 to 2.2 kWh on a normal cycle, with energy-saver cycles near 0.5 kWh
• Electricity rate: the US average is about 18 cents per kWh, but it varies by state
• Water per load: a new ENERGY STAR model uses under 4 gallons, older ones use 4 to 15
• Water and sewer rate: often around half a cent to one cent per gallon when both charges are counted

The calculator above turns those into a cost per load, then stretches it to a month and a year. Most of the cost is energy, and most of the energy goes to heating water rather than running the motor.

Two things are worth separating here. The pump and electronics use a steady, small amount of power, while the heating element is what swings the bill. A machine that heats its own water can use more energy than one that draws hot water from your water heater, because the water heater is often the cheaper source per gallon. The cost per load is an estimate, not a bill, so treat the calculator as a way to compare choices rather than a prediction to the penny.

Worked example: an ENERGY STAR load at 18 cents per kWh

Take a newer dishwasher that uses 1.5 kWh and 4 gallons per load, with electricity at $0.18 per kWh and water and sewer at $0.006 per gallon.

• Energy: 1.5 kWh times $0.18 = $0.27
• Water and sewer: 4 gallons times $0.006 = $0.024
• Total: about $0.29 per load

Now stretch it. One load a day is 365 loads, or about $106 a year. Five loads a week is 260 loads, or about $75 a year. Twenty loads a month lands near $5.80 a month.

Compare that to an older dishwasher from before 1994 that uses 12 gallons and 2.5 kWh. Energy is 2.5 times $0.18, which is $0.45, and water is 12 times $0.006, which is $0.07, for about $0.52 per load. That is 79% more per load, and roughly $190 a year at one load a day. Upgrading the machine is the single biggest lever on this cost.

Dishwasher cost per year for a family

How often you run the machine matters as much as the per-load cost. A family of four typically runs 150 to 250 loads a year. Here is what that looks like at $0.29 per load.

• 150 loads a year: about $44
• 200 loads a year: about $58
• 365 loads a year, one a day: about $106

ENERGY STAR puts a standard certified dishwasher at about $50 a year to run, which matches the 150 to 200 load range. If your number comes in far above that, the usual reasons are an old machine, a high electricity rate, or a hot wash and heated dry on every cycle. Each of those can be fixed, and the calculator lets you test the fix before you change anything.

Cost per load at different electricity rates

Electricity price is the biggest swing in the total. This table uses a 1.5 kWh load and 4 gallons of water, with water at $0.006 per gallon.

Rates run from under 12 cents per kWh in some states to over 30 cents in others, so the same dishwasher can cost three times as much to run depending on where you live. The EIA monthly electric price table lists the average residential rate by state, which is the number to use if your bill is hard to read.

Dishwasher versus washing by hand

The common belief is that hand washing saves money. For a full load, it usually does not. A dishwasher uses 3 to 5 gallons for an entire load, while hand washing a sink full of dishes can use 8 to 20 gallons of hot water, and every one of those gallons was heated by your water heater.

The gap comes from efficiency. A dishwasher pumps the same water through many dishes and heats only what it needs. A running tap sends fresh hot water down the drain. The dishwasher also does not leave the tap running while you scrub.

Hand washing wins only in one case: a very small number of dishes, washed in a basin rather than under a running tap. For everything else, a full dishwasher load uses less water and less energy. ENERGY STAR's dishwasher page explains the water savings in more detail, including the roughly 5,800 gallons a certified model saves over its life.

To compare fairly, count three things: the water, the energy used to heat it, and the detergent. A basin of hand-wash water at 110 F can hold 5 gallons, and heating those gallons costs more than the dishwasher uses for the same dishes. The savings from hand washing only show up when you use only a little hot water.

How to cut the cost per load

You cannot change the physics, but you can change how you use the machine. These steps cut the per-load cost without buying anything.

• Run full loads. The machine uses the same energy and water whether it is full or half full, so a full load spreads the cost over more dishes.
• Use the eco or energy-saver cycle. It uses less water and lower heat, which cuts the energy used to heat water.
• Turn off heated dry. Air drying saves a few cents a load, and over a year it adds up.
• Lower the water heater. A setting near 120 F is enough for most dishwashing and cuts the energy needed to heat the incoming water.
• Scrape, do not rinse. A quick scrape is enough. Rinsing dishes under a running tap wastes the hot water the dishwasher is about to use anyway.

One more option is a time-of-use electricity plan. If your utility charges less at night, running the dishwasher after peak hours can shave the energy cost. Check your rate plan before you rearrange your routine.

The best value comes from stacking these habits. A full load on the eco cycle with no heated dry, run at a low electricity rate, can cost under 15 cents. Run half full on the heavy cycle with heated dry at a high rate, and the same machine can cost over 60 cents. Same dishwasher, four times the cost.