Martin Lewis is back again with another interesting opinion on a common commodity. You may remember him warning against debit cards, but this time around, it’s the air fryer. Unfortunately, it is not very much in support of the convenient electronic kitchen appliance.

The air fryer has gained much popularity, especially since the pandemic and the subsequent increase in living costs. The kitchen appliance is advertised as being much healthier. They are also supposed to beat ovens on average operating costs. However, we may have jumped the gun on this small electric oven, and perhaps it is not all that is advertised.

Martin Lewis’ Honest Opinion On Air Fryers

In a recent The Martin Lewis podcast episode, Lewis explained that sometimes ovens are actually cheaper than air fryers. Martin, who is now 50, explained that microwaves provide consistent heat. However, ovens warm up to the highest they can get, then continue only to provide enough heat in spurts to maintain that temperature. As such, ovens do not spend the entire time going full power.

Martin Lewis even provides a specific scenario where ovens turn out to be much more cost-efficient. “If you were doing a full roast dinner and you were cooking many [jacket potatoes], it’s probably cheaper [putting them in the oven] than putting five or six jacket potatoes in a microwave because each additional object you put in a microwave, you need to keep it on longer because a microwave just heats the individual object”

However, do not take this as the absolute condemnation of the air fryer. For example, in the above case, if the number of jacket potatoes was just one instead of 10, the air fryer/microwave wins without any doubt. Be that as it may, we cannot be doing mathematics every time to figure out which option is cheaper for a given amount of food. Or, can we?

The Mathematics Behind The Cost-Efficiency In The Kitchen

To the previous question, Martin Lewis actually provides an equation that will give us the answer, along with its problem. “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 ($0.42) per hour of use. […]

The problem with the equation for heating equipment is an oven is going to be about 2,000W. 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 ($0.42) is about 6p, shall we say? So it’s 6p ($0.07) turning the microwave on for that amount of time. So yes it’s a very useful equation”. Just as a clarification, the equation works for air fryers as well.

Lewis even gets backing from a different source: The Money Edit. They conclude that the average running cost of an oven is 21p, whereas that of an air fryer is only 13.6p ($0.16). However, more powerful air fryers will naturally have higher average running costs. Some, like the 2000W one, cost 34p per average use. They also support the fact that the quantity of food is another important factor as Lewis explained.

As such, Martin Lewis draws a simple conclusion: “If you’re cooking something small and simple in there, it’s probably cheaper in the microwave and similarly the air fryer.”

This is not the first of Martin Lewis’ expert opinion on financial matters. He also discussed the danger behind debit cards in general. The money marketing expert also believes that one should move from debit cards to credit cards because credit cards offer fraud protection.