Do You Need to Preheat an Air Fryer? What Manuals Say

Ninja, Cosori and Instant tell you to preheat for 2 to 5 minutes, while America's Test Kitchen says most air fryers don't need it. Here's when it matters.

By Maksud · Published Sep 27, 2026

Do you need to preheat an air fryer? For most basket models, no. America’s Test Kitchen says many air fryers don’t require it, and none of its Air Fryer Perfection recipes call for it. Manufacturers still recommend 2 to 5 minutes.

Sources most often recommend it for crisp, seared or frozen foods like fries and wings, and Instant and KitchenAid build no preheat into their Reheat modes.

Kitchen Watcher is a research site. Nothing below comes from our own cooking; every number is attributed to the manual or page it came from, and the manufacturer figures are manufacturer-stated, not measured.

What Ninja, Cosori, Instant and KitchenAid say about preheating

The brands agree that a preheat helps, but not on how long it takes or how much it matters.

Ninja’s AF100-series owner’s guide says “We recommend 3 minutes of preheating” and tells you to use the built-in timer for the countdown. Its quick start guide adds that you should always preheat “for best cooking and crisping results.” The guide doesn’t describe a separate ready signal; the preheat is just a timer you set.

Cosori’s TurboBlaze manual (model CAF-DC601) goes further. It has a dedicated PREHEAT button, and it says food “will not cook thoroughly without preheating.” That’s the strongest claim from any source read for this page. It’s a manufacturer claim, and America’s Test Kitchen’s air fryer recipes skip the preheat entirely.

Instant’s Vortex Plus 6-quart guide builds the preheat in. After you press Start, the display shows “Preheating,” then “Add Food” when it’s done. Instant’s UK FAQ, which doesn’t name a model or temperature, says preheating “only takes 5 minutes.”

America’s Test Kitchen’s review describes a quick 2-minute preheat on the Vortex Plus 6-quart, and says its favorite models took about 2 minutes to reach 400°F. The two figures don’t match.

KitchenAid’s product help page on air fryer preheating, filed under its countertop ovens, takes the middle position. It says preheating is not necessary for all cooking modes but is important for consistent and even results.

How long to preheat an air fryer, by model

Every time and temperature below is manufacturer-stated or taken from America’s Test Kitchen’s published review. None of it is our measurement. For the models themselves, see our Ninja AF101 review, Cosori TurboBlaze review and Instant Vortex Plus 6qt review.

When does preheating an air fryer help?

The sources that favor a preheat tie it to crisping and searing. Each frames the benefit its own way:

• Ninja’s quick start guide ties the 3-minute preheat to “best cooking and crisping results.”
• Instant’s UK FAQ says most foods benefit from the immediate high heat of a preheated chamber.
• Cosori’s manual recommends preheating before any food goes in, unless the unit is already hot.

The Takeout lists foods it says benefit, including steaks, burgers, wings, frozen fries, pizza rolls, mozzarella sticks, salmon, bacon and baked goods. It calls 3 to 5 minutes standard but cites no manual. A Reviewed writer goes longer, preheating 5 to 7 minutes at 400°F.

The evidence is thin, though. None of these sources publish side-by-side results for preheated versus cold starts. The crisping benefit is the manufacturers’ and writers’ claim, not documented with numbers.

When can you skip preheating?

The sources point to a few cases where skipping is normal or built in:

• Roasted vegetables. The Takeout’s writer skips the preheat for roasted potatoes, broccoli and Brussels sprouts and cooks a couple of minutes longer. The same article says larger foods and anything you want seared do better with a preheat.
• Reheating leftovers. Instant’s Reheat program has no preheat by design, and KitchenAid doesn’t program one for Reheat either.
• Dehydrating. KitchenAid’s automatic preheat skips Dehydrate, Keep Warm, Toast and Bagel too.

America’s Test Kitchen goes further. Its Air Fryer 101 lists not needing a preheat as one of air fryers’ advantages over ovens. Its equipment review found a separate preheat cycle of up to 5 minutes on one model less convenient, not better.

If you skip it, America’s Test Kitchen’s Air Fryer 101 advice still applies: check doneness at the low end of the recipe’s time range and add time as needed. No source read for this page gives a fixed number of extra minutes; The Takeout’s “a couple of minutes” is one writer’s rule of thumb, not a measurement.

How to preheat an air fryer with or without a preheat setting

With a preheat button or automatic cycle:

• Cosori TurboBlaze: tap PREHEAT, adjust the temperature if needed, and add food when it beeps and shows “End.” The manual says preheat runs at fan speed 4.
• Instant Vortex Plus: choose your program and press Start. It preheats on its own, then shows “Add Food.” The guide doesn’t describe a way to skip it; add food when the prompt appears.

Without a preheat button, use Ninja’s method from the AF100-series guide. Set the temperature you’ll cook at, leave the empty basket in, and run a 3-minute countdown on the built-in timer. Then add the food and set the real cook time.

When converting an oven recipe, Ninja’s guide says to lower the temperature by 25°F; more on that in air fryer vs convection oven.

Does skipping the preheat affect food safety?

None of the manuals read for this page tie the preheat to food safety, though Cosori’s says food “will not cook thoroughly” without it. What decides safety is internal temperature: Ninja’s owner’s guide says to use a thermometer to check that food reaches the temperatures the FDA recommends, and to monitor the internal temperature of proteins. Do that whether you preheated or not, and add time if a cold start leaves food short.

What if your air fryer smokes or smells during preheat?

Instant’s guide requires an empty test run at 400°F for 18 minutes before first use, to check the unit works; for first-use odors, see new air fryer plastic smell. If the unit gives off black smoke, Ninja’s owner’s guide says to unplug it and wait for the smoking to stop before removing the basket, and why is my air fryer smoking covers the causes.

More on air fryers

• Best air fryers
• What size air fryer do I need?
• What a preheat costs to run
• Aluminum foil in an air fryer
• How we research