SmartTechDay

What each device costs to run

Sorted by how much power they draw, which is not the same as how much they cost you — a heater pulls fifteen times what a television does and runs a fraction of the hours.

Three questions this table answers

What draws the most

The Power column ranks devices by their peak wattage. A space heater at 1500 watts pulls fifteen times what a television draws, but only when it is actually on — the ordering by watts alone is not the ordering by cost.

What runs when nothing is happening

The Standby column shows what the device draws while switched off but plugged in. For a television, that is fractions of a watt; for a satellite terminal it is twenty. A dash means the device has no off-when-plugged-in state at all.

What it costs across a year

A year column collapses the two above into money at a published national tariff. The Basis column, right beside it, tells you exactly how each figure was reached — because two of our devices are certified per year and the rest are certified per watt.

What the devices you leave running cost for a year, at 4 hours a day. Devices used in minutes — a hair dryer, a toaster, a kettle — are left out on purpose: four hours a day is not their life, and putting them on the same axis would rank them at the top, which is the exact error this site exists to correct.
  • Water heater$655
  • Space heater$301
  • Tumble dryer$112
  • Window air conditioner$85
  • Refrigerator$80
  • Freezer$74
  • Dehumidifier$61
  • Dishwasher$44
  • PlayStation 5$35
  • Air purifier$28
  • Television$25
  • Starlink$24
  • Washing machine$20
  • Desktop computer$7.89
  • WiFi router$4.02
  • Computer monitor$3.48

measured annual consumptioncalculated from watts × hours

DevicePowerStandbyA yearOn what basis
How much electricity does an air purifier use?Air purifiernot published$28152 kWh/year, measured
How much electricity does a computer use?Desktop computernot published1.1–2.3 W$7.8943 kWh/year, measured
How much electricity does a dehumidifier use?Dehumidifiernot published$61335 kWh/year, measured
How much electricity does a water heater use?Water heaternot published$6553570 kWh/year, measured
How much electricity does a refrigerator use?Refrigeratornot published$80435 kWh/year, measured
How much electricity does a freezer use?Freezernot published$74405 kWh/year, measured
How much electricity does a washing machine use?Washing machinenot published$20110 kWh/year, measured
How much electricity does a dishwasher use?Dishwashernot published$44239 kWh/year, measured
How much electricity does an air conditioner use?Air conditionernot published$85462 kWh/year, measured
How much electricity does a dryer use?Tumble dryernot published$112608 kWh/year, measured
How many watts does a hair dryer use?Hair dryer1200–1875 W$4121538 W × 4 h/day
How many watts does an air fryer use?Air fryer1200–1875 W$4121538 W × 4 h/day
How many watts does a clothes iron use?Clothes iron1200–1700 W$3881450 W × 4 h/day
How many watts does a microwave use?Microwave1200–1500 W$3611350 W × 4 h/day
How much does a space heater cost to run?Space heater750–1500 W$3011125 W × 4 h/day
How many watts does a toaster use?Toaster1000–1500 W$3351250 W × 4 h/day
How many watts does an electric kettle use?Electric kettle1000–1500 W$3351250 W × 4 h/day
How many watts does a coffee maker use?Coffee maker1000–1200 W$2951100 W × 4 h/day
How many watts does a PS5 use?Games console46–217 W0.31–3.8 W$35132 W × 4 h/day
How much electricity does a TV use?Television83–102 W0.3–0.5 W$2593 W × 4 h/day
How many watts does Starlink use?Satellite internet75–100 W20–20 W$2488 W × 4 h/day
How many watts does a WiFi router use?Router3–27 W$4.0215 W × 4 h/day
How many watts does a monitor use?Monitor12–14 W0.15–0.3 W$3.4813 W × 4 h/day

Devices with no off state

Four devices in the list above run for 8,760 hours a year: a refrigerator, a freezer, a home router, and — if you have one — a Starlink terminal. For these, the meaningful figure is not peak wattage but yearly total, because there are no hours to multiply against. Even 20 watts held continuously is 175 kilowatt-hours a year, which is more electricity than several of our other devices use in a year doing their entire job.

For these four the calculator on the device page still asks for hours, but the honest reading is 24 a day. Setting fewer means you priced only the part that felt like use and left the rest out of the total.

Two units, two kinds of certification

The Power column above is not the same measurement for every row. A television, an air fryer, a monitor: these are certified in watts drawn at the wall. A refrigerator, a freezer, a washing machine: these are certified in kilowatt-hours consumed across a year, measured under a defined test cycle. Both figures come from recognised standards; they just answer different questions.

Multiplying an annual figure by hours would count the usage twice, because the test cycle behind it already includes a defined pattern of use. Multiplying a wattage by a year of continuous use would overstate the total for anything that spends most of the day off. The Basis column against every row names which calculation was used for that specific device.

Annual figures use 18.34¢ per kWh (U.S. Energy Information Administration, June 2026), and the basis column says how each one was reached. Devices certified in watts are run at the middle of their range for 4 hours a day. A dash in the standby column means the device has no standby mode rather than that we did not check.