How Much Does It Cost to Run a Rice Cooker?

Most household rice cookers are rated at about 300–700 W, and induction-heating (IH) models at around 1,200–1,350 W. We use 500 W as a typical figure. The heater runs at or near full power until the water is absorbed, and a batch takes about 30 minutes, so one batch uses about 0.25 kWh.

Cooking one batch a day costs about $0.05 a day in the US, £0.07 in the UK and €0.09 in Germany, or about $1.38, £2.00 and €2.75 a month.

A higher wattage mostly means faster cooking, not a bigger bill. The energy depends mainly on how much rice and water you heat. Sharp's KS-HF10B, a 5.5-cup (1-litre) cooker rated at 1,130 W, uses 171.3 Wh, about 0.17 kWh, to cook a batch on its eco setting.

After cooking, most rice cookers switch to keep-warm and stay there until you turn them off. Keep-warm uses only a small fraction of the cooking power. Sharp's KS-HF10B uses 18.8 Wh an hour on keep-warm, and China's efficiency standard allows up to 40 Wh an hour for cookers rated at 400 W or less and 50 Wh for those up to 600 W.

The hours add up. Six hours of keep-warm at 20–50 W uses about 0.1–0.3 kWh, as much as cooking another batch. Digital models also draw about 2–3 W when they're plugged in and switched off.

Habits vary widely. Japan's efficiency test assumes a 5.5-cup cooker makes 340 batches a year and keeps rice warm for 1,540 hours, about 4 hours a day. In Indonesia, a 2020 study by CLASP and Ipsos found that half of households that cook once a day keep their rice warm for 6–12 hours.

That's why the same appliance can use very different amounts of energy. Sharp rates the KS-HF10B at 90.7 kWh a year in Japan's test. CLASP estimated about 327 kWh a year for a typical 1.8-litre Indonesian cooker used 1.5 times a day and kept warm 7.2 hours a day, averaged across homes and small food stalls.

Basic rice cookers have a heating plate under the pot and a thermostat that switches to keep-warm once the water is gone. In Indonesia, 88% of rice cookers sold in 2018 used this kind of resistance heater, and CLASP found that most low-priced models had no insulation.

Micom (microcomputer or fuzzy-logic) cookers use a chip to adjust the heat through soaking, cooking and steaming. Zojirushi's 5.5-cup NS-ZCC10 is rated at 680 W, and the 10-cup NS-ZCC18 at 1,000 W.

Induction-heating (IH) cookers heat the whole inner pot with a magnetic field. They draw more power, such as 1,230 W for Zojirushi's 5.5-cup NP-HCC10, but for less time, and manufacturers claim slightly higher efficiency than basic models.

In Indonesia, where many homes have a supply limited to about 900–1,200 W, 80% of rice cookers sold in 2018 drew under 450 W, so they can run alongside other appliances. In the US and Canada, rice cookers run on 120 V outlets, and even 1,350 W IH models plug into a standard socket. Voltage doesn't change the cost; the energy used does.

Japan, South Korea, China and Indonesia all set efficiency rules for rice cookers. Since 2021, rice cookers sold in Indonesia carry the government's energy-saving label, rated from one to five stars.

Cooking figures are the rating on the label; the heater runs near full power for about half an hour per batch, and a batch typically uses about 0.15–0.3 kWh. Keep-warm and standby figures are averages. Use your cooker's label wattage in the calculator.

• Cook only what you'll eat soon, and switch the cooker off once the rice is served.
• For later meals, cool the rice quickly, keep it in the fridge or freezer and reheat it in a microwave instead of keeping it warm for hours. Japan's energy-saving guidance for rice cookers recommends exactly this.
• If you use keep-warm a lot, choose a well-insulated cooker. CLASP found that better insulation and warming control are the main ways to cut a rice cooker's energy use.
• Switch digital models off at the wall when you're not using them; they draw about 2–3 W even when idle.
• Keep the lid closed while cooking and on keep-warm so the heat stays in.
• In Indonesia, compare the stars on the energy-saving label (label tanda hemat energi); more stars mean lower energy use.

• Refrigerator
• Electric kettle
• Microwave
• Air fryer
• Bill analyzer