Finance guru issues warning about big problem with people using air fryers instead of ovens to cook food

Air fryers have been praised as a godsend for cutting costs and saving on energy bills.

I don't know about you, but weekday meals got a lot easier to make and prep since these mini ovens came about. You could say they're the best thing since sliced bread!

But what if this wasn't the case?

According to Martin Lewis, the UK's go-to expert on saving money, the truth about air fryers might be more complex than we thought.

Lewis explained that while the air fryer wins over for some types of cooking, it doesn't always turn out cheaper than using a regular oven.

In an episode of The Martin Lewis podcast, he explains that working out what's cheaper between an air fryer, a microwave and an oven requires some maths skills.

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Microwaves continuously produce heat while they’re on, whereas traditional ovens reach a set temperature and then simply maintain it.

This means ovens could be more efficient for meals that take longer to cook.

So, where are we at with air fryers?

Well, it's a little complicated but with a few calculations you can work it out, Lewis said.

Those who are closely watching their energy bills should look at the wattage of their appliances.

The money-saving expert breaks it down like this: 'General equation is, find the wattage of an item, then work out how many kilowatts or what fraction of a kilowatt it's using, then multiply that by 34p per hour of use.

'The problem with the equation for heating equipment is an oven is going to be about 2,000W.'

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For example, he said: 'If you had a 1,000W microwave and you put it on for 10 minutes, one KWH for a sixth of an hour, a sixth of 34p is about 6p, shall we say? So it’s 6p turning the microwave on for that amount of time. So yes, it’s a very useful equation.'

If maths isn't your thing and you just want a simple rule of thumb, here it is: cooking a small meal or food for one person is likely to be more efficient with an air fryer.

However, a word of caution from the financial journalist to those who host Christmas dinner: whilst it might seem quicker to bung everything in the air fryer, using the oven to cook multiple things at once might work out cheaper in the long run.