Does a slow cooker really use less than the oven?

A slow cooker draws a few hundred watts, an oven over 2,000; but the slow cooker stays on for many hours. Which one uses more depends on the recipe: this calculator compares the energy and cost of a cook in a slow cooker and in an electric oven, and tells you how much you save in a year.

It works in any currency: enter the energy price from your bill.

How the calculation works

• Slow cooker energy: power × cooking hours × share of time the element is on.
• Oven energy: power × oven hours, including preheating, × share of on-time.
• Cost: kWh × energy price; the annual saving multiplies the difference by cooks per week and by 52.

The thermostat switches the element on and off, so rated power is not actual use. After preheating, an oven is often on for about half the time; a slow cooker for a share that depends on its setting. A plug-in energy meter gives you the real values.

The comparison depends on the recipe

A 200 W slow cooker for 8 hours at 70% on-time (1.12 kWh), a 2,400 W oven at 50% on-time, two cooks a week, energy at 0.30 per kWh:

A slow cooker pays off above all for stews, braises and pulses, the dishes that would take hours in the oven. For a short bake the saving almost disappears.

How much frequency matters

With the base comparison (oven for 2.5 hours):

The saving grows in proportion to the number of cooks: someone who makes long dishes every day saves far more than someone who uses the slow cooker now and then.

The reading bands

• No saving: with these figures the slow cooker uses as much as or more than the oven.
• Below 25%: it uses a little less than the oven.
• 25% to 50%: it uses less.
• 50% to 75%: it uses much less.
• Above 75%: it uses a small fraction of the oven's energy.

Limits of the calculator

On-time shares are estimates: they depend on the model, the amount of food and how often you open the lid or door. The calculator compares cooking energy only: it ignores the heat the oven gives off to the home, welcome in winter and unwelcome in summer, and the fact that some recipes turn out better one way or the other. Gas ovens need a different comparison.

Frequently asked questions

How much electricity does a slow cooker use?

A 200 W slow cooker for 8 hours, with the element on 70% of the time, uses about 1.1 kWh: about 0.34 at 0.30 per kWh.

Does a slow cooker use less than an oven?

Often yes, for long cooks: in the example it uses about 63% less than an oven on for 2.5 hours. For short oven cooks the difference is small.

How much do you save in a year?

In the example, with two cooks a week, about 59 a year; with one a day, about 205.

Why enter the on-time share?

Because the thermostat cycles the element: a 2,400 W appliance does not use 2.4 kWh every hour.

How do I measure real use?

With a plug-in energy meter: plug in the slow cooker for a whole cook and read the kWh.

Is the low or high setting better?

The high setting generally cooks faster at higher power; the total energy can be similar. What matters most is how long the cook lasts.

Does the calculator work for a gas oven?

No, it compares with an electric oven only. Gas needs its own consumption and price.

Does lifting the lid increase energy use?

Yes: each time heat escapes and cooking takes longer, in both the slow cooker and the oven.

Does it work in any currency?

Yes. Enter the price per kWh in your currency.