Calculate the electricity cost of a slow cooker session.
A slow cooker is cheap to run despite the long hours because its power draw is tiny — typically 150-250 W on low, comparable to a bright light bulb and roughly a tenth of an oven. Eight hours at 220 W is only 1.76 kWh, so a full day of cooking costs less than half an hour of oven time. The reason is insulation and target temperature: a slow cooker holds its contents near 90 C inside a sealed, well-lagged pot, while an oven heats a large air cavity to 180 C and vents continuously. That is why the cheapest cuts and the cheapest method coincide, and why leaving one running all day is not the extravagance it feels like.
Slow cooker energy per session
Energy per cook = watts x hours / 1000; cost per cook = energy x rate per kWh; weekly = cost per cook x cooks per week; annual = weekly x 52
Substantially. A 220 W cooker for eight hours uses about 1.76 kWh; a 2.4 kW oven cycling at half duty for three hours uses about 3.6 kWh. The slow cooker wins on both energy and on being able to use cheaper cuts.
It draws more — often 300 W against 200 W — but it also reaches temperature faster and is usually run for half the time, so total energy is broadly similar. Low is marginally cheaper and much kinder to tough cuts.
They are designed for it, with sealed lids and no exposed elements. Standard precautions still apply: use it on a heatproof surface away from the wall, never with a damaged cord, and follow the manufacturer's instructions.