I bought one recently. It’s a game changer for me. It’s really just an oven that solves the main problem with ovens: being slow to heat / under powered. It’s really mind boggling that these took so long to hit the market!
[1] https://en.wikipedia.org/wiki/Halogen_oven
[2] http://www.lamptech.co.uk/Spec%20Sheets/TH%20SP%20IR%20Thorn...
Double ovens are a thing but you rarely see apartments outfitted with those and if you already have an oven, air-fryer makes more sense than replacing single oven with double oven.
My air fryer has a toaster oven form factor[1]. The fan is much more powerful however and it has extra heating elements. Otherwise it literally is a toaster oven with convection, even says so in the name!
Conceptually all of these are very similar, it’s just the balance of heating power and fan speed that make the difference, though marginal it may be from an engineering design standpoint.
Typical air fryers have a basket design[2] that helps with splatter control, but they are otherwise again the same.
I know nothing of the technologies involved but I suspect the air fryer makes things easier because it's easier to get the desired effects in a small heating area (the basket) than the oven.
This means it’s under powered. On top of that, the temperature might be high but energy delivery is not. That means the temperature right around the items actually drops, like how being still in cold water creates a static layer of warm water that keeps you warmer than if you’re moving around in it. With fast moving air you get significantly more heat transfer.
This is what convection ovens do but those are under powered in both heat and air flow, for my use case. Enough that I don’t use them at all, while I use my air fryer multiple times daily. Mine actually has the form factor of a toaster oven, so it’s a very easy comparison.
It’s literally just a stronger version of a convection oven, with different marketing.
> reduce energy use
I’m not so sure. It takes my air fryer much less time to cook things, so without doing the numbers I can’t say which is more efficient. I’d say that’s more about cost.
An oven that takes longer to get to temperature is wasting energy, not using less, because of greater waste from losses to the surrounding environment.
There's nothing about an air fryer that they couldn't have made them in the 50s. How did they take so long to exist??