How much electricity does a robot vacuum use per month in the UK?
A robot vacuum with a 14.4 volt, 5,200 mAh battery, such as the Roborock Qrevo S Pro, stores about 0.075 kilowatt hours, so a full recharge costs around 2.0p at the Ofgem cap rate of 26.32p per kWh. Charged once a day that is about 2.25 kilowatt hours and 59p a month. The dock adds its own use on top, about 76p a month if it idles at 4 watts, and up to 10.9p each time it dries the mops for three hours.
What a robot vacuum uses per clean
A robot vacuum costs about 2.0p for each full recharge, because a typical battery holds around 75 watt hours. Roborock fits the Qrevo S Pro with a 14.4 volt, 5,200 mAh lithium ion battery, and multiplying the two gives 74.9 watt hours. The robot is rated to take 20 volts at 1 amp from its dock while it charges, which is 20 watts, so refilling a flat battery takes the best part of four hours.
The motor that does the cleaning is small. Narwal, which makes robot vacuums of its own, puts typical robots at 20 to 100 watts while they work and most of them at around 40 to 65 watts, against 620 to 900 watts for a corded vacuum cleaner. A robot running for an hour and a half at 50 watts uses the same 0.075 kilowatt hours, which is why the battery size is the simplest way to put a ceiling on a single clean.
Work it out for your own robot vacuum, one full recharge
Type in the wattage from the plate on the back, then your own unit rate. The numbers update as you type.
What a month costs
| Pattern | Electricity a month | Cost a month | Cost a year |
|---|---|---|---|
| Full recharge every other day | 1.13 kWh | 30p | £3.60 |
| Full recharge every day | 2.25 kWh | 59p | £7.21 |
| Daily charge plus dock standby at 4 W | 5.13 kWh | £1.35 | £16.43 |
| Daily charge, standby and up to 3 hours of mop drying | 17.55 kWh | £4.62 | £56.20 |
The first two rows are the robot itself. The last two add the docking station, and the drying figure is the most the dock could use at its rated current, so a real drying cycle will usually come in under it. A smaller flat where the robot finishes with half its battery left costs roughly half of the charging figures.
| Appliance | Typical draw | Usage we assume | Per hour (UK) | Per usage (UK) | Per month (UK) | Per hour (US) |
|---|---|---|---|---|---|---|
| Robot vacuum, one full recharge | 20 W | per full recharge of a 14.4 V 5,200 mAh battery | 0.53p | 2.0p | 59.9p | 0.37 cents |
Rates: Ofgem cap 1 October to 31 December 2026 at 26.32p per kWh (source), EIA residential average June 2026 at 18.34 cents per kWh (source). Checked 2026-09-22.
Where the dock adds to the bill
A basic charging dock does little more than pass power to the robot. The larger self emptying, mop washing stations do far more, and Roborock's manual for the Qrevo S Pro dock gives two ratings at 220 to 240 volts. During dust collection it is rated at 3 amps, about 690 watts at 230 volts, while the suction pulls the robot's bin into the bag. The rest of the time, which covers washing the mops in water at 75 degrees and drying them with warm air at 45 degrees, it is rated at 0.6 amps, about 138 watts.
Emptying only runs while the bin is pulled into the bag, and even a full minute at the rated 690 watts would use about 0.0115 kilowatt hours, which is 0.30p. Drying is the part that adds up, because it runs for hours after every mopping session. The manual says the drying time can be changed in the app and that auto drying can be switched off.
| Mop drying time after each clean | Most it can use at 0.6 A | Most it can cost | Daily for a month |
|---|---|---|---|
| 2 hours | 0.28 kWh | 7.3p | £2.18 |
| 3 hours | 0.41 kWh | 10.9p | £3.27 |
| 4 hours | 0.55 kWh | 14.5p | £4.36 |
Standby on the dock
A robot vacuum spends almost all of its life parked. Narwal puts the standby draw of a robot vacuum at 3 to 5 watts, and at 4 watts that is about 35 kilowatt hours over a year, which is £9.22. That is more than a year of daily full recharges at £7.21, so if your dock idles at that level, a vacuum only robot spends more on waiting than on cleaning. Robot vacuums are also outside the ecodesign rules that cap the power of mains vacuum cleaners.
Against a corded vacuum
One full recharge at 2.0p against 18.4p for an hour with a 700 watt corded machine makes the robot look like the cheap option, and per clean it is. Across a year the comparison is closer. An hour a week with a corded vacuum comes to 36.4 kilowatt hours, while a robot charged every day and left on its dock at 4 watts reaches about 62 kilowatt hours before any mop drying. The robot is doing seven cleans to the corded machine's one, so it is still good value for the work, but it will not cut your bill if you are replacing a weekly vacuum with it.
Ways to cut what a robot costs
The dock is where most of the saving sits, and most of it is controlled in the app.
- Shorten the mop drying time or turn auto drying off in a warm, dry room, since the manual only recommends longer drying for humid conditions.
- Run the robot every other day if the floors allow it, which halves the charging figure.
- Switch the dock off at the wall when you go away, because a week of standby at 4 watts costs about 17.7p for nothing.
- Keep mopping for the rooms that need it and run vacuum only cleans elsewhere, so the dock washes and dries the pads less often.
What this costs in the United States
At the EIA residential average of 18.34 cents per kilowatt hour, charging a 75 watt hour robot once a day costs about 41 cents a month and $5.02 a year. In California, at 34.74 cents, the month is about 78 cents, and in Texas at 15.94 cents about 36 cents.
Common questions
How much electricity does a robot vacuum use?
A full battery on a typical modern robot holds about 75 watt hours, so a daily clean that runs it flat uses around 2.25 kilowatt hours a month. Narwal puts robots at 20 to 100 watts while cleaning and 3 to 5 watts on standby, and a dock that washes and dries mops can use more than the robot itself.
How much does a robot vacuum cost to run per month in the UK?
About 59p a month to charge a 75 watt hour battery once a day at the cap rate of 26.32p per kWh. With the dock idling at 4 watts that rises to about £1.35, and a mop dock that dries for three hours after every clean can take the month to as much as £4.62.
Does a robot vacuum use electricity when it is docked?
Yes, a small amount. Narwal puts standby at 3 to 5 watts, which over a whole year at 4 watts comes to about 35 kilowatt hours and £9.22, more than a year of daily charging. Switching the dock off at the wall stops that, but the robot cannot recharge until you switch it back on.
Is a robot vacuum cheaper to run than a normal vacuum?
Per clean, yes. A full recharge costs about 2.0p against 18.4p for an hour with a 700 watt corded vacuum. Because a robot runs every day and sits on its dock all year, its yearly total can end up close to, or above, an hour a week with a corded machine.