Bar length is what each appliance costs; the hollow end of a bar is standby — power drawn while it sits plugged in and unused. The line running down the chart is the cumulative share, so you can see how few things you would actually have to change.
The arithmetic here is sound and the total is real, but it answers a narrower question than it looks. Adding up appliances gives you the energy half of an electricity bill. Several things sit outside it, and one of them is large.
Most electricity contracts charge a fixed daily fee before a single kilowatt-hour. In the UK that is currently around 60p a day — about £219 a year — payable if you go on holiday for twelve months and switch everything off at the wall.
It is not a rounding error. Against this page’s UK rate of 26.11p/kWh:
| Household | kWh/yr | Energy | Standing charge | Share of bill |
|---|---|---|---|---|
| Low use, one person | 1,500 | £392 | £219 | 36% |
| Typical | 2,700 | £705 | £219 | 24% |
| Family of four | 4,200 | £1,097 | £219 | 17% |
| Heat pump and an EV | 9,000 | £2,350 | £219 | 9% |
So the lighter your usage, the more this page understates your bill — by roughly a quarter for a typical home and over a third for a small flat. It also inverts the usual advice: for a very low user, switching to a tariff with a lower standing charge saves more than any amount of unplugging.
Every figure assumes a single price per kilowatt-hour all day, all year. Real tariffs are often time-of-use (cheap overnight, expensive at teatime) or tiered (the first block of units at one price, the rest at another). If you are on an EV or heat-pump tariff, the average rate is not the rate you pay for the thing that matters.
The presets are typical figures for a class of appliance. A fifteen-year-old fridge can use two to three times what a new one does; a heat-pump tumble dryer uses roughly half a vented one. Anything running around the clock is entered as an average wattage with its duty cycle already folded in — a fridge is 55 W average, not the 150 W on its plate — which is why you should not "correct" it for the compressor cycling.
Not modelled at all: space heating and cooling, which for most homes dwarfs everything on this list and depends on weather, insulation and thermostat habits rather than on a wattage and an hours-per-day.
Grid intensity is quoted as one number per country, but the real figure swings by a factor of three or more across a single day as wind and solar come and go. For anything you can time — an EV, a dishwasher, a washing machine — when you run it changes the emissions far more than which appliance you chose. Verified against energy_model.py, which now also pins all 33 appliance presets and 16 country tariffs to this page.
Every appliance has a power rating in watts — how fast it uses energy while running. Multiply by how long it actually runs and you get kilowatt-hours (kWh), the unit your electricity bill is priced in. Multiply that by your rate and you have a cost. Do it for everything you own and you can see, at a glance, what's actually driving your bill — usually not what you'd guess.
A fridge drawing an average 55 W, running continuously, uses about 480 kWh a year — roughly $85 at the US average rate. A single 1,500 W space heater running 4 hours a day uses more electricity than that fridge in about six weeks.
The other half of the story is the hours an appliance is not being used. A microwave drawing 2 W for its clock is idle about 8,670 hours a year, which is 17 kWh — a sixth of what the same microwave uses actually cooking. It is small per device and it is not small once you count them all.
That's the pattern worth internalising: heating, cooling and drying appliances draw ten to thirty times the power of electronics and lighting, so a little time on a heater or dryer outweighs a lot of time on a laptop or a lamp.
Less than the internet usually claims, but not nothing. Modern regulations cap most appliances at around 0.5–1 W on standby, and anything left plugged in draws that for roughly 8,700 hours a year — so 1 W costs about 8.8 kWh annually, a couple of dollars. The catch is the count: ten idle devices at 2 W each is 175 kWh, which is a real line on a bill for electricity that did nothing at all. Enter a standby figure against any appliance in your list and the chart splits it out. Anything running 24/7 — a fridge, a router — has no idle hours, so it has no standby to add.
Typical, commonly-cited nameplate or average-running figures for each appliance type — a starting point, not a measurement of your unit. Check the rating label or a plug-in energy meter for the real number, then edit the value here.
It fits both kinds of appliance with one model: things that run continuously (a fridge — 24 hours, 7 days) and things used in short bursts (a dishwasher — 1 hour, 5 days a week). Multiply watts × hours × days ÷ 7, scaled to a year, and both work the same way.
Total kWh used × the selected country's average grid carbon intensity (kg CO₂ per kWh) — a rough figure that reflects the country's electricity mix (coal and gas grids run high, hydro and nuclear-heavy grids run low). It changes with the seasons and the seconds; treat it as an order-of-magnitude estimate.
Because the price of electricity itself varies enormously — roughly 4–5× between the cheapest and most expensive major economies, driven by energy mix, import dependence, and tax and levy policy. The "Compare countries" section shows exactly how much your specific list would cost elsewhere.
Releases in which this page changed, newest last. Derived from the archived copy of every release, not from notes written afterwards — so it reflects what actually shipped. Site-wide passes are left out; they are in the full changelog.