Air fryers became a sensation partly on the promise of slashing cooking bills, and there is truth in it, but also a fair amount of overstatement. An air fryer is essentially a small, fast fan oven, and its savings come from that smallness, not from any special efficiency. For one or two portions it genuinely undercuts a big oven. For a family roast it does not. This guide puts real pence on a session at current UK prices, shows exactly when the saving is real and when it vanishes, and compares the air fryer with the microwave so you can place it correctly in your kitchen.
The short answer. A typical air fryer pulls 1 to 2kW but only for a short cook, so a 15 to 20 minute session costs around 7p to 17p at 26.11p per kWh. Against a big oven that has to preheat a large cavity, that is a real saving of perhaps 20p to 30p a meal for one or two portions. But the edge shrinks to nothing once you are cooking enough to fill the oven, because several air fryer batches use as much energy as one ovenful. It saves pence per meal on small jobs, not pounds across the board.
Why it can save: smallness, not magic
An air fryer is not a clever new technology. It is a small fan oven with a fast heating element and a strong fan that blows hot air around the food. Its saving over a full oven comes entirely from its size.
A full-size oven has a large cavity to heat, plus shelves, a door and a big volume of air, and it takes several minutes to come up to temperature before you even start cooking. Bake a modest portion in it and you waste a lot of energy heating empty space. An air fryer heats a tiny chamber almost instantly and circulates the heat tightly around the food, so for one or two portions it does the job in less time and far less energy. For chips, a couple of fillets, roast vegetables for two or reheating something you want crisp, the saving over firing up the big oven is genuine.
That is the honest version of the air fryer pitch. Not a magic efficient appliance, just a right-sized one for small jobs. The waste it removes is the empty oven space you were heating for nothing.
What a session actually costs
Air fryers are usually rated 1 to 2kW, but they only draw full power while heating and cycle on and off once up to temperature, so the average draw across a cook is lower than the nameplate figure. Here is what a session costs at 26.11p per kWh.
| Cook | Power (avg) | Time | Energy | Cost |
|---|---|---|---|---|
| Reheat / small bake | ~1.4 kW | 10 min | ~0.23 kWh | ~6p |
| Chips for two | ~1.5 kW | 20 min | ~0.50 kWh | ~13p |
| Chicken pieces for two | ~1.5 kW | 25 min | ~0.63 kWh | ~16p |
| Same chips in a 2kW oven (with preheat) | ~2 kW avg | 35 min | ~1.2 kWh | ~31p |
At 26.11p per kWh electricity, Ofgem cap July to September 2026. Assumes the element cycles on and off once up to temperature, so average draw is below the nameplate rating. Worked examples; your model and cooking times will differ.
So a real air fryer session is a few pence to about 16p, and it saves roughly 15p to 20p a meal against the same small job in a big oven. That is a genuine saving, but it is pence per meal, not pounds. To see your own figure, put your model's wattage and a realistic cook time through the running cost calculator, or measure it directly with a plug-in energy monitor.
When it does not save
The advantage shrinks or vanishes as the quantity grows. This is the part the marketing skips.
Cooking a large family meal in several small air-fryer batches can use as much energy as one ovenful, and take longer overall because you are waiting between loads. A roast for six, a big tray bake or anything that needs real capacity belongs in the oven, where that large heated space is doing a lot of work at once and the cost per portion is low. The oven is only wasteful when it is heating a vast cavity for one small dish.
So the air fryer wins on small, quick jobs and loses on big batch cooking. It complements the oven rather than replacing it. Crucially, buying one will not cut your bills if you still reach for the oven for everything substantial and just use the air fryer occasionally. The saving only lands if the air fryer genuinely replaces oven sessions you would otherwise have run for small meals. Our oven, microwave or air fryer comparison lays out which appliance wins at which scale.
Air fryer versus microwave
For the specific job of reheating, the microwave usually beats the air fryer on cost, because it puts energy straight into the food and heats no chamber at all. Reheating a plate of leftovers might cost under 2p in the microwave against 6p or more in the air fryer.
What the air fryer gives you that the microwave cannot is texture. It crisps and browns where the microwave leaves things soft. So the sensible split is: microwave for plain reheating where texture does not matter, air fryer when you want the result crisp, oven for anything big. Use all three for what each does best and you spend the least overall. Reheating chips or a roast potato is the classic case where paying the air fryer's few extra pence buys a far better result than the microwave.
| Job | Cheapest tool | Rough cost |
|---|---|---|
| Reheat a plate of leftovers | Microwave | ~2p |
| Reheat chips, want them crisp | Air fryer | ~6p |
| Chips or fillets for two | Air fryer | ~13p |
| Roast or batch for six | Oven (full) | ~13p per head |
At 26.11p per kWh electricity, Ofgem cap July to September 2026. Worked examples.
What changes the running cost
Two air fryers cooking the same chips can cost different amounts, so it helps to know what moves the figure.
- Wattage. A 2kW model heats faster but draws more while doing it. Higher wattage usually means a shorter cook, so the total energy is similar, but a slow, underpowered unit that takes longer can cost more overall.
- Capacity and load. A big dual-basket air fryer heats more space, so cooking one small portion in a large unit wastes some of the air fryer's own advantage. Cook a basket that suits the food, and do not run it half-empty if a smaller batch would do.
- Preheat habit. Many people preheat out of oven habit. The small chamber heats almost instantly, so most foods can go straight in, saving a few minutes of energy each time.
- Cooking from frozen. Frozen food takes longer and costs a little more than fresh, the same as in any oven, so it is the cook time that drives the cost, not anything special about the appliance.
None of these is dramatic, but together they explain why a careless air fryer session can cost as much as a careful oven one. The appliance is a tool, and the cost follows how you use it. Measuring a few real cooks with a plug-in energy monitor tells you exactly what your model does in your kitchen, which is more reliable than any headline figure.
Where it sits, and setting expectations
Think of the air fryer as the right-sized tool for small, quick cooking, alongside the microwave for plain reheating and the oven for big batches. Used that way it genuinely trims cooking energy, a few pence at a time, and the convenience and crisp results are a bonus on top. Bought as a miracle that pays for itself in weeks, it will disappoint, because the saving is pence per meal and the appliance itself is not specially efficient.
A few habits squeeze more from it. Skip the preheat where the food does not need it, since the small chamber heats almost instantly anyway. Do not overfill the basket, or the air cannot circulate and the cook takes longer. And switch it off at the wall when not in use, as some models draw a little on standby, covered in our standby power guide.
Cooking energy is only a slice of the electricity bill, so do not expect the air fryer alone to transform it. For the bigger picture, the main electricity hub gathers the appliance guides together, and the slow cooker is the other cheap-cooking workhorse worth knowing about for long, low one-pot meals.