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Running the robot itself costs very little — a full charge holds under 0.1 kWh, which is well under a cent at the current US average rate. The dock is the part with real wattage: ECOVACS publishes 1,650W for hot-water mop washing and 650W for dust collection. Almost no other maker publishes anything.
This question gets asked before buying and it almost never gets a straight answer, because the answer requires numbers that most manufacturers do not print. What follows is the arithmetic on the figures that genuinely exist, with the source on each, and an honest account of how much is missing.
What each maker actually publishes
We checked the manufacturer product pages for the models we cover. The result is lopsided in a way that is worth seeing laid out.
Published electrical specifications, manufacturer product pages, checked 2026-09-09
Maker and model
Battery
Robot rated power
Station rated power
Charge time
ECOVACS DEEBOT X8 PRO OMNI (since discontinued)
6,400mAh at 14.4V, Li-ion
80W
1,650W mop washing; 650W dust collection
4h 37min
Roborock Qrevo Curv (since discontinued)
6,400mAh, voltage not stated
Not stated
Not stated
Not stated
Dreame X50 Ultra
Not stated
Not stated
Not stated
Not stated
eufy Omni C28
Not stated
Not stated
Not stated
Not stated
iRobot Roomba Combo j9+
Lithium-ion, capacity not stated
Not stated
Not stated
Not stated
One maker of five publishes enough to calculate anything. Roborock states a capacity but no voltage, and without voltage a milliamp-hour figure cannot be converted to watt-hours — so even that row cannot be turned into a cost without assuming a number Roborock has not given us.
The robot: genuinely trivial
Take the one model with a complete published spec. ECOVACS states 6,400mAh at 14.4V for the X8 Pro Omni - a model it has since marked sold out, though it still publishes the specification, and its successor the X9 PRO OMNI carries the same 6,400mAh cell. Multiply those and you get the energy the battery holds:
6.4Ah x 14.4V = 92.2Wh, or 0.0922 kilowatt-hours per full charge.
The US average residential electricity price was 18.34 cents per kilowatt-hour in June 2026, per the EIA. At that rate a full charge is about 1.7 cents.
Charged once a day for a year, that is roughly 34 kWh, or about $6.20.
One honest caveat on those figures: 92.2Wh is what the battery stores, not what the charger pulls from the wall. Charging is not perfectly efficient and no manufacturer here publishes a charging efficiency, so the true figure is somewhat higher. It is still small. Nobody has ever needed to worry about the vacuuming part of a robot vacuum's electricity bill.
The dock: where the actual watts are
This is the part nobody talks about, and it is the reason this page exists. ECOVACS publishes two station figures for the X8 Pro Omni: 1,650W for warm-water mop cleaning and 650W for auto dust collection. The first is a kettle-class heating element sitting in your hallway.
The obvious next question is what those cost per cycle, and here we hit the limit of what is published. ECOVACS states the power ratings but not how long each cycle runs, and a rating without a duration is not an energy figure. Rather than invent a cycle length, here is the arithmetic per minute, which you can multiply by whatever your own machine actually does:
Cost per minute of station operation, at the June 2026 US average rate
Station function
Published rating
Energy per minute
Cost per minute
Warm-water mop cleaning
1,650W
27.5Wh
about 0.50 cents
Auto dust collection
650W
10.8Wh
about 0.20 cents
Arithmetic: watts divided by 60 gives watt-hours per minute; that divided by 1,000 and multiplied by $0.1834 gives the cost. Both ratings are from the ECOVACS product page; the electricity rate is the EIA US residential average for June 2026. We have not measured either cycle's duration and do not publish a per-cycle total.
What that table tells you in practice: even a generous five minutes of hot-water washing per run is about two and a half cents, and dust collection cycles are famously short. The dock is where the watts are, and it is still not a large bill. The reason to know the numbers is not that they are alarming — it is that nobody else will give them to you at all.
Standby, which nobody publishes
A dock is plugged in and awake around the clock. It listens for the robot, keeps the network connection alive, and on the washing stations may keep water in a tank. Standby draw is therefore the one number that runs 8,760 hours a year rather than a few minutes a day, which makes it the figure most worth having.
Not one manufacturer whose page we checked publishes it. That is a genuine gap in the published data rather than an oversight on our part, and it is the single figure we would most like to add to this page. If a maker publishes one, or you find one in a manual we have missed, tell us and we will add it with the source.
What actually moves the number
Whether the dock heats anything. A station that washes mop pads in hot water and dries them with warm air has heating elements; a plain charging dock does not. That is the difference between a 1,650W component and none.
How often it runs. Daily scheduled cleaning uses roughly seven times the energy of a weekly run, which sounds obvious and is the largest single lever you control.
Suction mode. The fan is the robot's largest draw and it scales steeply, which is the same reason max suction shortens runtime — see runtime and battery life.
Whether it finishes in one charge. A robot that runs flat and has to top up mid-clean spends energy on charging overhead twice. On a large floor that is a real difference — see robot vacuums for a large house.
Carpet. Carpet boost raises fan power and driving through pile costs more at the wheels than rolling on tile.
How this compares to the rest of the running cost
Put the electricity next to the consumables and the picture changes shape. Brushes, filters, mop pads and dock bags are bought several times a year at real prices; the electricity for the same year is a few dollars on the one model where we can calculate it. For almost every household the consumables are the running cost and the power is a rounding error.
That is worth knowing before you optimize the wrong thing. If running cost is your concern, the lever is replacement parts and what they cost you — an anti-tangle brush that lasts longer saves more per year than any plausible difference in electricity between two models.
How we picked
Criteria first, products second. These are the things we ranked on, stated before anything is recommended.
Whether the maker publishes enough electrical data to answer the question at all — battery capacity AND voltage, robot wattage, station wattage.
Whether the machine has a heating element in the dock, since hot-water washing and hot-air drying are where the large numbers live.
Published runtime, because a robot that finishes the floor in one charge draws less than one that needs two.
Whether there is a powered dock at all. No dock means no standby draw and no heating cycle, and that is the genuinely low-energy answer.
We did not rank on estimated consumption. Only one maker publishes enough to calculate it, so a ranking on calculated cost would be a ranking on our own guesses.
What we did not do: test any of these machines. We do not own one, we do not have a lab, and nothing on this page is written as though we did. The full method.
Quick picks
Ranked on the published specifications below. Tap a row to jump to the full write-up.
#
Product
Best for
Suction
Price
1
ECOVACS DEEBOT X9 PRO OMNIThe roller mop that washes itself continuously while it runs rather than pushing one increasingly dirty pad around, now with a cyclone-directed anti-tangle brush.
Roborock Q7 M5+The Q7 M5's LiDAR and anti-tangle hardware, plus the self-emptying dock the plain M5 does not come with — and a stated bag capacity to go with it.
Every figure in this table is linked to the page it came from in the write-ups below. We have not tested any of these machines.
Top pick
ECOVACS DEEBOT X9 PRO OMNI
Mopping that rinses as it goes
The roller mop that washes itself continuously while it runs rather than pushing one increasingly dirty pad around, now with a cyclone-directed anti-tangle brush.
Self-emptying into a 3L bag, with temperature-controlled mop washing stated from 40C to 75C (104F to 167F) and hot-air dryingECOVACS publishes a wash temperature RANGE rather than a single figure, and states selectable drying durations of 2, 3 or 4 hours.Source: ECOVACS DEEBOT X9 PRO OMNI product page — station (retrieved 2026-10-03)
What it does well
OZMO Roller self-washes during the run rather than only at the dock
Publishes a threshold figure and states the condition (with mop attached)
Mop washing is temperature-controlled across a stated 40C to 75C range rather than a single number
What it does not
20mm climb is among the lowest published figures here
0.22L on-board bin is small, so it leans hard on the dock
16,600 Pa is lower than the model it replaces, which stated 18,000 Pa
Who it is for
Hard floors that actually get dirty — kitchens, entryways, homes with dogs.
Skip it if
Your sills are tall. ECOVACS publishes 20mm with the mop attached, which is at the low end of our threshold table.
Five-function Omni station: self-cleaning mop, auto hot-air drying, auto dust emptying into a stated 3L sealed bag for up to 75 days, auto tank refilling and auto wastewater collectionThe 3L bag and the 75-day interval were added on 2026-10-24 after re-reading eufy's own C28 page; they were missing from this sheet before. eufy states no filtration rating for the bag and no electrical figures for this machine at all.Source: eufy Omni C28 product page — Omni station, 3L bag and 75-day interval (retrieved 2026-10-24)
What it does well
HydroJet roller rinses itself during the run instead of only at the dock
A stated 15,000 Pa, which is a real figure rather than a multiple
Five-function station: mop washing, hot-air drying, dust emptying, tank refill and wastewater collection
What it does not
No published threshold height and no published mop-lift height
No published runtime, bin capacity or body height either
The roller is a consumable and eufy does not state a replacement interval
Who it is for
Hard floors that get genuinely dirty, on a budget that will not reach a flagship omni station.
Skip it if
Your home has thresholds or deep carpet. eufy publishes no climb height and no mop-lift height for this model, so you cannot check either before you buy.
Nothing to do with the machine, which is the most capable on this site, and everything to do with this specific question. Dreame publishes no battery capacity, no voltage, no robot wattage, no station wattage and no charging time for it on its own product page. It also has one of the largest stations here, with hot-water washing and hot-air drying, so it is precisely the model whose dock draw a cost-conscious buyer would most want to know. If running cost is the question you are trying to answer before buying, you cannot answer it for this model from published data, and we are not going to estimate it for you.
The short version
Do not choose a robot vacuum on its electricity consumption. On the only model where the manufacturer publishes enough to calculate it, running the robot itself costs single-digit dollars a year, and the dock's heating elements — the genuinely large numbers — run for minutes rather than hours. Choose on the things that actually differ between machines, and treat this page as the answer to a question rather than a criterion.
If the underlying question is whether the whole thing is worth buying, the electricity is the smallest input to it. The full set of conditions is on are robot vacuums worth it.
Questions people actually ask
+ How much power does a robot vacuum use?
The robot itself uses very little. ECOVACS publishes 80W for the X8 Pro Omni and a 6,400mAh 14.4V battery, which works out at 92.2Wh — under 0.1 kWh — per full charge. The station is the higher-draw part, at a published 1,650W for hot-water mop washing.
+ How much does it cost to run a robot vacuum per year?
On the one model with a complete published spec, charging it daily for a year is roughly 34 kWh, or about $6.20 at the EIA's June 2026 US average residential rate of 18.34 cents per kWh. That excludes station cycles and standby draw, neither of which is published with a duration.
+ Do robot vacuum docks use electricity when idle?
Yes — a dock is powered around the clock to listen for the robot and keep its network connection alive. No manufacturer we checked publishes a standby figure, which is frustrating because it is the one draw that runs all year rather than for a few minutes a day.
+ Does a self-emptying dock use a lot of power?
It has the highest rating in the system but runs briefly. ECOVACS publishes 650W for auto dust collection, which is about 0.2 cents per minute of operation. The hot-water mop washing element is higher at a published 1,650W, or roughly 0.5 cents a minute.
+ Which robot vacuum uses the least electricity?
Structurally, one with no powered dock — no heating element and no station standby draw. We cannot rank models on measured consumption because only one maker of the five we checked publishes enough data to calculate it, and we will not estimate the others.
+ Is a robot vacuum expensive to run?
No. On the only model where the figures exist, the electricity is a few dollars a year. Consumables — brushes, filters, mop pads, dock bags — cost considerably more, so that is where to look if running cost matters to you.
