How Much Does It Cost to Run a Dishwasher? (Certified Data vs. Hand-Washing)

A certified dishwasher's electricity use clusters hard around 239–240 kWh a year — out of 677 models in WattCost's dataset, the vast majority sit within a single kWh of the top of that range, with only a small efficient tail running as low as 80 kWh.

What a certified dishwasher actually costs

The certified annual figure assumes 215 wash cycles a year — the DOE test procedure's standard of roughly 4 loads a week — and includes the energy to heat the water inside the machine, not just run the motor and pump. At the US average electricity rate, the median certified dishwasher costs $45.00 a year to run. ENERGY STAR's own estimate for a standard-size certified model is about $50 a year, which lines up closely once you account for the fact that ENERGY STAR's figure isn't weighted toward any specific rate.

The spread between models is real but modest by appliance standards: the most efficient certified dishwasher in the dataset, the Loch L1126, uses 80 kWh a year; the least efficient, the Zline DWS3-24, uses 240 kWh — a 3x gap, versus the nearly 20x gap refrigerators show. Dishwashers are a much more homogeneous category to shop in.

Dishwasher vs. hand-washing: the actual numbers

This is the comparison most people actually want, and the data doesn't support the instinct that hand-washing is the frugal choice. The EPA-backed ENERGY STAR program estimates that washing dishes in a certified dishwasher rather than by hand cuts utility bills by about $220 a year and saves roughly 8,400 gallons of water, because a full load in a modern certified machine uses a fraction of the hot water a sink full of running water does. The efficiency comes from using less hot water per dish, not from the electricity side alone — which is also why running a dishwasher half-empty erases most of the advantage.

Loading it right matters more than the model you buy

The efficiency case falls apart if the dishwasher runs half-empty: a full load spreads the same base water-heating cost across more dishes, while a half load throws away most of the advantage over hand-washing. Skipping the pre-rinse under the tap matters just as much — a modern certified machine's soil sensors and spray arms are built to work without it, and pre-rinsing just reintroduces the hot-water use the dishwasher exists to eliminate.

Your state changes the number more than most models do

At the national average rate, the median dishwasher costs $45.00 a year. In North Dakota, the cheapest electricity in the country, that drops to $29.52. In Hawaii, the most expensive, it rises to $111.42 — a 3.8x swing for the identical machine, larger than the gap between the most and least efficient certified models.

Running one load a day works out to 365 cycles a year, well above the 215-cycle DOE basis; running one every three days lands closer to 120. A household near the 215-cycle assumption will see its bill and the certified figure agree closely — one washing dishes daily should expect a bill somewhat higher than the label suggests, and one running a load every few days should expect somewhat lower.

What actually moves the number

• Cycle count. The 215-cycle DOE assumption is a national average — a household running loads daily will exceed it; one running every few days will come in under.
• Water heating. Most of a dishwasher's energy goes into heating water, not spinning the pump, so a unit's internal heater efficiency matters more than its motor.
• Your electricity rate. A 3–4x rate difference between states moves the dollar cost by the same multiple, independent of the machine.

FAQ

Is it cheaper to hand-wash dishes or use a dishwasher? Using a certified dishwasher is cheaper for most households — ENERGY STAR estimates about $220 a year in savings versus hand-washing, driven mostly by lower hot-water use.

How many kWh does a certified dishwasher use per year? Certified models in WattCost's dishwasher dataset range from 80 to 240 kWh a year, with most clustered near the top of that range.

Which dishwashers are the most efficient? See the most-efficient certified dishwashers and the models at least 10% more efficient than the federal minimum for the full ranked lists, or the cheapest dishwashers to run leaderboard.

Does dishwasher running cost vary much by state? Yes — the same certified dishwasher costs $29.52 a year in North Dakota versus $111.42 in Hawaii, purely from the electricity rate.

What usage assumption does the certified kWh figure use? 215 wash cycles a year, the DOE test procedure's standard basis, which also bakes in the energy used to heat the wash water.