Air fryers are sold on capacity, which is a shame, because capacity is close to the least useful thing to know about one. The number on the box refers to the volume of the basket, and volume is not the constraint. Surface area is. Food browns when hot air reaches it, and food stacked two deep in a tall basket does not brown — it steams, then disappoints, and then gets shaken halfway through in the hope of rescuing it.
What actually decides whether an air fryer earns its place is much duller: whether it fits under your cupboards, whether you can lift it, and whether the basket is wide enough to lay a portion out in a single layer. Every one of those questions points towards a smaller machine than most people end up buying.
Surface area beats volume, every time
Think about what you actually cook. Chips, chicken thighs, halloumi, roast vegetables — all of them want space around them. A basket that is deep rather than wide gives you more litres and less usable cooking area, because the top of a pile shields the bottom of it from the airflow that makes the whole thing work.
This is why two machines with identical stated capacities can behave completely differently. A wide, shallow drawer cooks a portion for two in one go. A tall, narrow one of the same volume cooks the same portion in two batches, badly, and takes longer overall than the oven you were trying to avoid.
When comparing models, ignore litres and find the internal dimensions. Width times depth is the number that matters. If a manufacturer does not publish it, that is itself informative.
The counter-depth problem
Standard kitchen worktops leave a limited gap between the surface and the underside of the wall cupboards. Air fryers exhaust hot air upwards and backwards, which means they need clearance above and behind — usually more than people expect, and more than the footprint alone suggests.
A large machine frequently cannot live where you want it. It ends up pulled out for every use and put away afterwards, and an appliance that has to be carried is an appliance that gets used a third as often. The single best predictor of whether an air fryer becomes a daily tool or a cupboard occupant is whether it can simply stay where it is.
Measure the space before you shop. Depth of worktop, height to the cupboard, and clearance behind. Then treat those measurements as the specification, and capacity as the thing you fit around them.
Single basket, dual basket, or oven style
| Type | Best for | Trade-off |
|---|---|---|
| Single drawer | One or two people, everyday cooking | One food at a time, so timings have to be staged |
| Dual drawer | Two components of a meal finishing together | Much wider footprint; each drawer is smaller than it looks |
| Oven style with shelves | Households replacing a small oven entirely | Slower to heat, harder to clean, weaker browning at the top shelf |
| Lid attachment for a multicooker | Kitchens with no spare worktop | Compromised at both jobs, and heavy to reconfigure |
Dual drawers are the format most often bought for a reason that does not survive contact with reality. The appeal is cooking two things at once; the catch is that each drawer is roughly half the size, so a household that needed a large single basket now has two small ones. They make sense when you routinely cook a protein and a vegetable that need different temperatures. They make no sense as a way to get more capacity.
Oven-style models deserve a word of caution for the opposite reason. They look like the flexible choice because they take shelves, but shelves reintroduce the exact problem air frying solves: food on a lower shelf sits in the shadow of the one above it. In practice most people end up using a single shelf, which means they bought a large, slow appliance to do the job a small fast one would have done better.
Cleaning decides how you feel about it
The part of an air fryer you will interact with most, after the basket, is the crisper plate at the bottom — and it is the part most likely to make you resent the machine. Look for a basket and plate that are genuinely dishwasher safe, and for a non-stick coating on a plate you can lift out rather than one moulded into the basket.
Also look at the underside of the heating element. In most machines it is exposed, it splatters, and it needs wiping. Models that make this awkward to reach acquire a smell within a few months that no amount of basket washing fixes.
Who this isn’t for
Skip an air fryer if you regularly cook for four or more. At that point you are running three or four batches, the machine is slower than the oven, and the energy advantage disappears along with the convenience. The honest recommendation for larger households is a good oven tray and a hotter oven.
Skip it too if your kitchen has no permanent spot for it. An appliance that lives in a cupboard is used for the first fortnight and then not at all. And skip it if what you actually want is a fast oven for baking — air fryers are convection ovens with aggressive fans, and that fan is unkind to anything that needs to rise gently.
What to know before you buy
- Measure the worktop first, including height to the cupboard and clearance behind. Buy to fit that.
- Find the basket dimensions, not the litres. Width times depth is your real capacity.
- Check the weight. Anything you have to lift regularly should be light enough to lift comfortably.
- Confirm the crisper plate lifts out and that both it and the basket are dishwasher safe.
- Listen to one running if you can. Fan noise varies enormously and is not on any spec sheet.
- Ignore preset buttons. Time and temperature are all you will use after the first week.
Does an air fryer really use less energy than an oven?
For small portions, yes — it heats a much smaller space and needs almost no preheating. For large portions cooked in batches, the advantage narrows and can reverse, because you are running the machine several times over. The saving is real but it is a small-portion saving.
Can I put foil or baking paper in one?
Usually, with a caveat that matters: nothing loose. The fan moves air hard enough to lift a sheet of paper into the heating element, which is a genuine fire risk. Use perforated liners weighed down by food, and never preheat with an empty liner in the basket.
Is a more expensive model better?
Above the budget tier, price mostly buys build quality, a quieter fan and better coatings rather than better cooking. The cooking difference between a mid and a premium machine of the same format is small. Spend the difference on basket size and shape instead, and read five questions before any large purchase before going further up the range.
The useful reframing is to stop thinking of an air fryer as a small oven and start thinking of it as a very fast grill with a fan. That tells you what it is superb at, what it is mediocre at, and why a wide shallow basket beats a tall roomy one. Buy for the space you have and the way you actually eat, and you will end up with a smaller machine that gets used far more. If counter space is genuinely tight, our small kitchen cookware roundup covers what to prioritise instead.
