How Does an Air Fryer Work?

An air fryer cooks food with fast-moving hot air instead of a bath of oil. A heating element warms the air, and a powerful fan drives it around a compact cooking chamber at high speed. The result is chips, vegetables and chicken that are crisp on the outside and tender inside, using little or no added oil.

That's the short answer. But what's actually happening inside the machine? Why does food come out crispier than in a fan oven, when both use hot air? And how much does an air fryer really cost to run? This guide walks through the technology step by step, from what's inside the appliance to practical cooking times and everyday tips.

How an air fryer works: the basic principle

Strictly speaking, "air fryer" is a misleading name. Nothing is fried in fat. The appliance works like a small, particularly powerful fan oven, only faster and more intense. Three things work together to make that happen.

The heating element and fan

In most air fryers, a coil-shaped heating element sits at the top of the cooking chamber, with a fan directly above or beside it. Depending on the model, the element heats the air to roughly 40–230°C. The fan sets that hot air moving and pushes it down into the chamber at speed.

From there, the shape of the chamber and the perforated base of the basket guide the airflow. The air travels down the sides, underneath the food and back up again. This closed loop surrounds the food with heat from every direction, which is why many dishes only need turning once, or not at all.

Three kinds of heat at work

An air fryer uses all three ways that heat can travel:

1. Convection: The fan circulates hot air around the food. This is the main cooking method, and the speed of the air is what makes the difference.
2. Radiation: The heating element sits close to the food and radiates heat directly onto its top surface. This helps with browning.
3. Conduction: The basket and crisper plate heat up too, and pass heat into the food where they touch it.

This combination produces a very intense transfer of heat. That is why the results are closer to frying than to baking.

Why does food go crispy? The Maillard reaction explained

Golden chips and crisp chicken skin are the result of a chemical process called the Maillard reaction. It starts at around 140°C on the surface of food. Amino acids and sugars react with each other, creating the familiar roasted flavours and golden-brown colour.

For the Maillard reaction to begin, the surface of the food needs to be dry and hot enough. This is where an air fryer shines. The fast airflow carries moisture away from the food's surface as soon as it evaporates, so the surface dries, heats up and starts to brown. It's similar to what happens in hot oil, but without the oil bath.

Why a small cooking chamber makes such a difference

If the principle is the same, why is the result often crispier than in a fan oven? It comes down to three factors:

1. Small volume: An air fryer's cooking chamber usually holds just a few litres. The air heats up faster, and the heat stays concentrated around the food.
2. Faster airflow: The fan sits closer to the food and moves air far more intensely within that small space than the fan in a full-size oven.
3. Short heat-up time: Many models need little or no preheating, and reach their target temperature within a few minutes.

The faster hot air moves across the surface of food, the more efficiently heat is transferred. So the compact design doesn't just save space on your worktop. It directly affects how your food turns out.

What's inside an air fryer?

The basket and crisper plate

Food sits in a removable basket or on an insert with a perforated base. Those holes matter. They let hot air reach the food from below, and they allow fat released during cooking to drip into the drawer underneath.

Many baskets have a non-stick coating so food releases easily and cleaning is simpler. For details of the materials and coating on a particular model, check its product specifications.

Single basket vs dual basket: what's the difference?

Air fryers come in two main designs:

• Single-basket models have one cooking chamber and one basket. They're more compact and ideal if you usually cook one thing at a time.
• Dual-basket models have two separate baskets, often each with its own heating element and fan. You can cook two different foods at the same time, at different temperatures and for different times: chips in one drawer and vegetables in the other, for example. A sync function lets both baskets finish at the same moment.

The right choice mostly depends on your household size and how you cook. If you regularly make complete meals with several components, a dual-basket model makes sense. For quick single dishes, a single basket is usually enough.

Ventilation and safety features

Not all of the circulating air stays inside the appliance. Vents at the back or top release some of it in a controlled way, which regulates temperature and humidity in the chamber. Because you're cooking with little or no oil, there's far less of the lingering fried-food smell you get from a deep fat fryer.

Typical safety features include automatic shut-off when the basket is pulled out, a timer that switches the appliance off, and an insulated outer housing. Models with a viewing window and interior light let you check on your food without opening the basket, so the heat stays inside.

Air fryer vs deep fat fryer vs fan oven

All three heat food, but in very different ways:

*Check your model's instruction manual to see whether the basket and accessories are dishwasher safe.

Does air frying use less oil than deep frying?

The most obvious difference from a deep fat fryer is the amount of oil. Instead of submerging food in several litres of hot oil, an air fryer needs a teaspoon at most, depending on the dish, or none at all. Food cooked this way absorbs correspondingly less fat.

A note on browning: when any starchy food is cooked at high temperatures, whether in the oven, a frying pan or an air fryer, over-browning can produce a substance called acrylamide. The Food Standards Agency's advice is to "Go for Gold": aim for a golden yellow colour or lighter when cooking starchy foods like potatoes and bread, and follow the cooking instructions on the pack. With moderate temperatures and the cooking times below, that's easy to do in an air fryer.

Can an air fryer replace your oven?

In short: for lots of everyday meals, yes; for everything, no. An air fryer is quicker, more compact and better suited to smaller portions. Your oven is still the better choice for large quantities, full trays, bread and traditional baking. For a detailed look at which appliance suits which cooking habits, see our guide: air fryer vs oven.

How much electricity does an air fryer use?

Air fryers typically have a power rating of around 1,400 to 1,800 watts. On paper, that's similar to an oven. The real difference is running time. The small chamber heats up quickly, preheating is often unnecessary, and many dishes are ready sooner.

Because the appliance runs for less time and heats a much smaller space, energy use per meal is often lower than with a full-size oven, especially for small portions and short cooking times. Actual consumption depends on the model, the food and how you use it.

You can estimate the cost yourself in three steps:

1. Convert watts to kilowatts: 1,500 W = 1.5 kW.
2. Multiply by cooking time in hours: 1.5 kW × 20 minutes (0.33 hours) = 0.5 kWh. In practice, usage is usually lower than this, because the element switches on and off to hold the temperature once it's heated up.
3. Multiply by your electricity unit rate: You'll find this, in pence per kWh, on your energy bill or supplier app.

Air fryer temperatures and cooking times

Most air fryers can be set from around 40–80°C up to 200–230°C, depending on the model. As a starting point:

All times are a guide and may vary depending on your model, the amount of food and the size of the pieces. Always check that meat and poultry are cooked through, piping hot in the middle with no pink meat, before serving.

For a complete chart covering vegetables, meat, fish and frozen foods, including how to convert oven recipes, see our air fryer cooking times guide.

Do you need oil, and if so, which one?

An air fryer works perfectly well without added oil. That said, a small drizzle or spray, about a teaspoon, makes many foods crispier and helps seasoning stick.

Choose an oil with a high smoke point, as temperatures in the chamber get high. Rapeseed, sunflower or vegetable oil all work well. Extra virgin olive oil has a lower smoke point and is better at lower temperatures; for high-heat cooking, a light or refined olive oil is the better choice.

5 tips for better results

1. Don't overfill the basket. Air needs room to circulate. If pieces are piled on top of each other, they'll cook unevenly. As a rule of thumb, fill the basket no more than two-thirds full.
2. Cut food to a similar size. Evenly sized pieces cook through at the same time.
3. Shake or turn halfway through. For chips, vegetables and snacks, give the basket a shake at the halfway point so everything browns evenly.
4. Season the oil, not the food. Dry seasoning on dry food can get blown around by the airflow. Mix your seasoning into the oil and coat the food with it instead.
5. Preheat briefly for delicate foods. Most dishes don't need it, but for steak or pastry, 2–3 minutes of preheating gives a more even result from the start.

Is an air fryer worth it?

At heart, an air fryer is a compact, high-powered fan oven: a heating element, a strong fan and a small cooking chamber. Together, they deliver fast, even cooking with little oil and crisp results. It's especially useful for households that often cook small to medium portions, want quicker mealtimes, and are looking for a simple alternative to a deep fat fryer or firing up the oven.

Whether you're after a compact single-basket model or a dual-basket air fryer for complete meals, you can compare the full range of COSORI air fryers.

Frequently asked questions