The short answer
Electricity: 2p per full charge for a typical 0.075 kWh battery, about £7 a year if the robot cleans daily. Add £10–£30 a year if the dock washes and hot-air-dries the mops after every run. Consumables: £40–£90 a year for dust bags, filters, brushes and mop pads. Total: roughly £50–£130 a year to own a docked robot vacuum, against a few pounds of electricity for a cordless stick that you push yourself.
per full charge (0.075 kWh)
robot electricity per year, daily cleaning
all-in-one dock, mop drying, per year
bags, filters, brushes, pads per year
The robot: pennies
Robot vacuum batteries are small — 2,600 to 6,400 mAh at 14.4 V, which is 0.04 to 0.09 kWh. At 26.32p/kWh a full charge costs 1p to 2.4p. Chargers lose 10–15%, so call it up to 3p. A robot that runs once a day uses one charge a day: £4–£10 a year. The listings on Amazon.co.uk rarely publish the watt-hour figure, which is why our product cards say 'not published' rather than inventing a number.
The dock: where the electricity goes
A self-empty dock runs a strong suction motor for 10–20 seconds per clean — fractions of a watt-hour. All-in-one docks are different: after each mopping run they wash the pads and then dry them with warm or hot air for one to four hours. Manufacturers that publish the heater power quote several hundred watts for the drying stage, and some flagships heat washing water to 60–100 °C. That lands at 0.1–0.3 kWh per session, 3p–8p, or £10–£30 a year at daily mopping. Docks that air-dry at room temperature (eufy Omni C20) use far less; docks that heat water and dispense detergent (Roborock Saros 20 Neo) use the most. Set mopping to two or three times a week if you want to cut it.
Consumables: the real bill
| Item | Typical interval | Typical cost per year |
|---|---|---|
| Dust bags (self-empty dock) | Every 6–8 weeks | £10–£25 |
| HEPA filter | Every 2–3 months | £8–£20 |
| Side brush(es) | Every 3–6 months | £5–£15 |
| Main roller brush | Yearly | £10–£25 |
| Mop pads | Every 3–6 months | £8–£20 |
| Cleaning solution (if the dock dispenses it) | 1–2 bottles a year | £10–£20 |
Brand-name packs cost more than third-party ones; Roborock and eufy both sell annual kits. £40–£90 a year is a fair planning figure, which is five to ten times the electricity.
Robot vacuum vs cordless stick vs corded vacuum
A cordless stick at 0.1–0.2 kWh per charge costs 3–5p per charge and a corded vacuum at 600–900 W costs 16–24p an hour, so per clean they are all in the same few-pence range. The robot's advantage is not electricity; it is that it cleans every day without you. Its disadvantage is the consumables and the dock. If you are choosing on money alone, a stick vacuum wins; if you are choosing on time, the robot wins.
The robots we recommend
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Frequently asked questions
Does leaving the robot on the dock all the time waste electricity?
Trickle-charging and standby draw a few watts: at 3 W continuously that is about 26 kWh a year, £6.90. Most docks drop lower once the battery is full. It is the price of having the robot ready.
How often should the dock dry the mops?
After every wet run, or the pads smell. If you mop daily, the drying cycle is the biggest electricity item; mop two or three times a week and you cut it accordingly without the robot vacuuming any less.
Can I use cheaper third-party bags and filters?
Usually, and they are often half the price. Filters and brushes are the parts where quality varies most; bags are generally fine. Check the robot's warranty terms first.
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