Guide · Kitchen
Air fryer or oven: what the numbers actually say
The energy argument is real but smaller than claimed, and it is not the reason most people end up using one.
An air fryer is a small convection oven with a fan close to the food. That is the entire technical story, and understanding it explains both why the results are good and why the energy claims are overstated.
The energy argument goes like this: an air fryer draws around 1,500 watts against an oven’s 2,000 to 2,500, and it needs almost no preheating. Both parts are true. But an oven at 2,000 watts is not drawing 2,000 watts continuously — it cycles the element to hold temperature, and a well-insulated oven cycles less. The honest saving on a portion for two is real but modest, and it shrinks as the quantity grows, because the air fryer’s advantage is its small cavity and a small cavity is exactly what limits it.
Usable basket volume, not quoted litres
That limit is the specification to check first: usable basket volume, not quoted litres. Manufacturers quote the total cavity, and food needs a single layer with air moving around it to get the result people buy these for. A quoted five litres is comfortable for two portions and cramped for four, and stacking defeats the mechanism entirely.
What an air fryer is genuinely better at than an oven is anything that wants a dry, fast, high-convection heat on a small quantity: reheating, chips, breaded things, roasted vegetables for two. What it is worse at is anything large, anything that needs even radiant heat, and anything baked. It will not replace an oven for a Sunday roast and it was never designed to.
The preheat is the real reason
The real reason most households keep using one is not energy and not results. It is the preheat: three minutes instead of fifteen changes what you are willing to cook on a weeknight, and that changes behaviour in a way the specification sheet cannot express.
Two things to check before buying: whether the basket and tray are dishwasher safe, because they are the parts that get greasy and they are the reason unused air fryers end up in cupboards; and how loud the fan is, since it runs for the entire cook and lives on a worktop rather than behind an oven door.