Appliance Running Cost Calculator

Wattage is a bad guide to cost

The number on the sticker is the draw at full tilt, and it tempts everyone into the same mistake: assuming the low-wattage appliance is the cheap one. A slow cooker draws about a twelfth of what an oven does and still costs almost as much to cook a stew, because it runs for eight hours instead of two and a half. Cost is watts multiplied by hours, and the second term is the one people forget.

The other half of it is the duty cycle. An oven does not hold 2,400 W for an hour — it pulls full power to reach temperature, then switches the element on and off to stay there, averaging perhaps 60 per cent across the session. A sous vide circulator is more extreme again: full power for ten minutes to bring the bath up, then a trickle to hold it. Anything with a motor, and a kettle, has no thermostat at all and draws its full rating the whole time it is on.

Where the real money is

Almost none of it is in the appliance you were worried about. In a typical Australian kitchen the ranking is consistent:

• The oven, by a wide margin, because it heats a large insulated box for a long time. Using an air fryer or a multicooker for anything that fits in one is the single biggest saving available.
• An espresso machine left switched on. Forty-odd watts sounds trivial until you multiply it by 8,760 hours. It is genuinely possible to spend more on standby than on coffee.
• The kettle, not because each boil is expensive but because there are so many of them. Filling it to the line you need rather than to the top is a real, if small, saving repeated several times a day.
• The dishwasher, where nearly all the energy goes on heating water rather than running the pump. An eco cycle takes longer and costs less, which feels wrong and is true.
• The dehydrator, which nobody expects. Ten hours at 500 W is more energy than a roast dinner.

Reading your own bill

Look for the usage charge, quoted in cents per kilowatt-hour. That is the number to type above. If you are on a time-of-use plan you will have two or three of them — peak, shoulder and off-peak — and cooking dinner almost always lands in peak. If you have solar, the sum that matters is your feed-in tariff rather than your usage rate, because running the dishwasher at noon costs you the few cents you would have been paid for exporting instead.

The daily supply charge is deliberately left out here. It is a fixed fee for being connected, it applies whether you cook or not, and folding it into a per-meal figure would only make every appliance look worse without changing which one to reach for.

The savings that are actually worth having

Match the appliance to the job rather than buying a more efficient version of the wrong one. A slow cooker beats the oven for a long braise; an air fryer beats both for anything under half an hour; the microwave beats everything for reheating. Keep the oven door shut — every look costs about 15°C and the element has to make it back. Use residual heat: switch a fan-forced oven off five or ten minutes early and let the cavity finish the job.

And boil what you need. If you want to be precise about that, the cups and grams converter will tell you how much water a recipe actually calls for, and the slow cooker converter will tell you how long the cheaper appliance needs.