Slow cookers are up to three times more expensive to run than induction hobs

Rocketing energy prices have forced many people to tighten their belts and become more efficient with their gas and electricity use.

That includes how we heat our homes, do the washing, and even the way we cook.

Slow cookers have soared in popularly ever since energy prices began to rise, with the perception that they use less energy than a lightbulb.

But is that strictly true? Not quite, according to the consumer group Which?.

In fact, tests have revealed that induction hobs use significantly less energy and are cheaper to run when it comes to some cooking tasks.

Which? carried out two experiments to see how the methods compared in terms of cooking time, energy used and the total cost of this energy.

The first involved making vegetable soup, while the second focused on beef stew.

In both cases, the old adage ‘slow and steady wins the race’ certainly didn’t come to fruition, as the induction hob proved superior in every category. 

Which? calculated the energy that was used based on the length of time it took make each dish, then equated this to a cost based on the current average price of a unit of energy under the government’s Energy Price Guarantee — 34p per kWh.

The slow cooker took 182 minutes to make the vegetable soup, which involved using an estimated 0.901 kWh of energy.

As expected, the induction hob was much quicker.

Using this method took just 26 minutes by comparison, and because of this, the energy use was much lower — at 0.273 kWh.

When putting a price on this energy use, the soup cost more than three times as much to make with the slow cooker than the induction hob.

The former came it at 31p, while the latter was just 9p. 

It wasn’t just in cost, energy use and time that the induction hob was victorious, it was also deemed ‘perfect’ on the tastebuds thanks to its ‘well-cooked vegetables and smooth consistency after puréeing’, according to Which’s expert testers.

The soup from the slow cooker was also well-cooked but not as smooth, the consumer group said, and was also very ‘thick as too much liquid evaporated during cooking’.

That being said, Which? acknowledged that even though it was a more expensive and less effective method, the ‘convenience of slow cooking can’t be denied’ because it means you don’t have to ‘watch over a saucepan for hours’.

When it came to cooking the beef and vegetable stew, the induction hob once again beat the slow cooker on energy consumption. 

The stew took just over an hour and a half on the induction hob and cost 23p in energy, while the slow cooker took around four hours and cost nearly twice as much in terms of heating.

This time the induction hob didn’t have things all its own way, however.

That’s because Which’s lab experts found that the stew made in the slow cooker was slightly better than the one cooked on the induction hob. 

Although the vegetables were a little overcooked, the meat was tender and the stew had a good consistency, the consumer group said.

By comparison, the stew made on the induction hob ‘was too thin and the meat was a little dry’.

This is not the first time that Which? has looked at how energy efficient different kitchen appliances are.

The group previously found that air fryers proved up to three times cheaper than a conventional oven to run, and cooked the food equally as well or even better.

However, because air fryers can cost anywhere between £30 and £300, the group said it may take time for any savings made on running costs to offset the purchase.

Microwaves, pressure cookers and slow cookers were also found to have lower running costs than ovens, but did not always give the best results in Which’s tests.

In terms of the lightbulb claim, it is true that on the face of it slow cookers should be more energy efficient than induction hobs because they require less power to run.

For instance, the slow cooker Which? used was rated at 320W, whereas the induction hob was 7.2kW (or 7,200W). 

But even though they need less power, they’re used for much longer, so end up costing more.

‘There has been a big surge of interest in slow cookers in recent months as millions of households across the country are feeling the pressures of the cost of living crisis. But our research shows that they might not be the cheapest way to cook,’ said Which? energy editor Emily Seymour.

‘Slow cookers are said to use less energy than a lightbulb. 

‘However if you’re thinking of buying one to help save energy and you already own an induction hob, it might not be worth it as our testing found induction hobs use less energy to make the same meals, making them cheaper to run.’

She added: ‘Slow cookers do come with added convenience, as you can get a bowl of steaming hot soup without having to stand watch over a saucepan, although the cooking process can take a few hours.’

In conclusion, Which? said that if you already own an induction hob, it makes sense to use it for cooking things such as soups and stews, rather than investing in a slow cooker specifically to carry out these jobs. 

However, the consumer group said that ‘slow cookers do have the added advantage of being able to chuck everything in and do something else while you wait’.

For this reason, you might choose a slow cooker for the convenience, just don’t expect it to save you money on your energy — or for it to be cheaper than a lightbulb.