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For reheating, the microwave is better and uses the least electricity; the air fryer makes food crispy. Neither can fully replace the other.
Short answer: the microwave is better for quickly reheating soups, stews, rice and veg: for small amounts it uses the least electricity, and it often retains vitamin C even better than a saucepan of boiling water. The air fryer is better when you want things crispy. Neither is healthier across the board.
What really matters: in the microwave, heat food in glass or ceramic rather than plastic and stir it; in the air fryer, cook potatoes and bread until golden rather than dark brown. Below you'll find the comparison with the oven, which appliance suits you, how to convert oven recipes and what's behind the microwave myths. How long everything takes in the air fryer is in the cooking times table.
The microwave heats the water in the food directly. The air fryer is a small fan oven that moves hot air around the food very quickly; the oven is a big one. That decides what each one is good for:
| Comparison | Microwave | Air fryer | Oven |
|---|---|---|---|
| Time | 2–8 min | 8–25 min | 20–45 min plus preheating |
| Electricity | around 14% | around 24% | 100% |
| Vitamins | often well retained | nothing leaches out | nothing leaches out |
| Crispy | no | yes | yes |
| Fat | none | often 1 tsp oil | a little |
| Best for | soup, rice, leftovers with sauce, defrosting | chips, roast veg, fish, chicken | traybakes, bakes, large amounts |
| Watch out for | glass instead of plastic, stir | golden rather than brown | golden rather than brown |
In short: liquids and leftovers with sauce go in the microwave, crispy food in the air fryer, large amounts in the oven. The times are for one portion. The electricity figures are for a jacket potato (oven = 100%) and come from a test by the UK consumer organisation Which?: the microwave took 8 minutes and used about a seventh of the oven's electricity, the air fryer about a quarter (Which? 2022). For the comparison with figures for chips, see Air fryer or oven.
Neither is healthier across the board. The microwave cooks quickly and with little water, so water-soluble vitamins such as vitamin C are often well retained (Lee et al. 2018). The air fryer needs far less fat than a deep fryer, but when starchy foods such as potatoes brown, acrylamide forms – just as in the oven. More on this in the article Is the air fryer healthy?.
If the recipe only gives oven settings, set the air fryer about 20 °C lower and allow a good half to three-quarters of the time. Veg is ready fastest, frozen food takes longest, and potatoes and chips never go above 180 °C. Check from halfway through.
Not entirely. For crispy food and small oven dishes, it's the better choice. But soups, sauces and drinks are hard to reheat in the basket, and defrosting takes longer. If you often reheat soup, stew or meal prep, you'll usually keep the microwave.
A combination microwave with hot air saves space and is worth it if your kitchen is small and you use both regularly. For the hot-air mode you need heatproof dishes, as in the oven – no plastic. The instruction manual tells you what's allowed in combination mode.
Anything with sauce or liquid goes in the microwave: covered, and stirred halfway through. Leftovers that should stay crispy – pizza, chips, fried potatoes, roast veg, breaded food – go in the air fryer, usually for a few minutes at around 160 to 180 °C. Rice is better reheated in the microwave: covered, with a splash of water – in the air fryer it dries out. Whichever appliance you use, the food has to get properly hot all the way through, especially meat, poultry and rice (more on this below).
If the packet gives a different wattage from your microwave, the wattage calculator converts the time: 3 minutes at 800 watts becomes 4 minutes at 600 watts.
Every cooking method changes food: heat breaks down delicate vitamins, and water-soluble compounds leach into the cooking water – in a saucepan as much as in the microwave. What counts is temperature, time and the amount of water. The microwave heats the water inside the food directly, so it cooks quickly and with little water. That keeps more of the water-soluble vitamins. A Korean study compared blanching, boiling, steaming and microwaving for several vegetables: vitamin C was generally best retained after microwaving and worst after boiling in water (Lee et al. 2018). The German Federal Office for Radiation Protection (BfS) concludes that, if you follow the cooking instructions, the changes in nutritional value are the same as with conventional heating.
The often-quoted "97 per cent loss of vitamin C in broccoli" comes from a Spanish study from 2003 – and it isn't about vitamin C at all, but flavonoids (Vallejo et al. 2003). The broccoli was cooked in water; boiling in a saucepan lost 66 per cent, steaming lost almost nothing. A follow-up study showed that losses in the microwave depend mainly on cooking time and the amount of water (López-Berenguer et al. 2007). The fact check by Correctiv, a German fact-checking newsroom, comes to the same conclusion: the microwave does not simply "destroy nutrients".
In practice: cook vegetables like broccoli briefly, covered, with two or three tablespoons of water – better to check once halfway than to let it run too long.
No. Microwaves are high-frequency electromagnetic fields, not ionising radiation – they produce heat, nothing else. According to the BfS, measured leakage averaged about 1 per cent of the limit; for appliances in good condition the BfS sees no risk, including for pregnant women and young children. If the door is bent or the seal is damaged, have the microwave checked or replace it.
The problem you can actually back up with evidence is the container, not the microwave. In a study from the University of Nebraska, microwaving released the most micro- and nanoplastic particles from plastic containers – far more than storage did (Hussain et al. 2023). The tests used water and diluted acetic acid; the health effects are not yet clear. The takeaway is still simple: heat food in glass or ceramic – it costs nothing extra.
Which containers work for meal prep is covered in detail in the article Reheating food in plastic.
The microwave heats unevenly. But reheated food needs to get properly hot all the way through: the consumer advice centre in North Rhine-Westphalia (Verbraucherzentrale NRW) advises stirring halfway and making sure meat and rice in particular reach at least 70 °C throughout.
Babies: the US health agency CDC advises against thawing or warming breast milk in the microwave, because hot spots can scald a baby's mouth and nutrients can be lost (CDC). A bowl of warm water is better; always stir baby food from the microwave thoroughly and check the temperature.
An air fryer is a small fan oven with very fast-moving air: food turns crisp with very little fat. Compared with deep-frying you save a lot of fat and calories, and for small portions it often uses less energy than the oven, according to the consumer advice centre in Bavaria (Verbraucherzentrale Bayern).
What it doesn't solve: acrylamide. It forms when starchy foods such as potatoes or bread brown, whatever the appliance – according to the BfR (German Federal Institute for Risk Assessment) from about 120 °C, with a sharp rise from 170 to 180 °C. The BfR's rule of thumb: golden, not burnt – ideally no higher than 180 °C and no longer than needed.
And: frozen chips have less fat from the air fryer, but they don't become fresh food. Where it really shines is veg, chickpeas, fish or chicken with a teaspoon of oil – you'll find ideas in our air fryer recipes.
The oven is ideal for large amounts such as tray-roasted veg or bakes, but slow for a single portion; the same acrylamide rule applies to roast potatoes. The frying pan works well for reheating rice, pasta and veg: medium heat, a splash of water, lid on. With steaming, hardly anything leaches into the water, which suits veg, fish and potatoes. On materials: Healthy cookware. How fat and effort compare is covered in Air fryer or frying pan. A good frying fat is olive oil, for example, which proved heat-stable in frying trials (Casal et al. 2010).
For vitamins, the biggest lever isn't the appliance but this: little water, short cooking time, don't overcook. For large amounts and meal prep, the oven stays practical; recipes: Meal prep recipes.
Common mistakes: heating in plastic containers or under cling film; not stirring leftovers and eating them only lukewarm; cooking chips and roast potatoes until dark brown.
The microwave for reheating, the air fryer for anything crispy. Soups, stews, rice and veg reheat fastest in the microwave, using the least electricity. Chips, roast veg, pizza and breaded food only get crispy in the air fryer.
Not entirely. For crispy food and small oven dishes, it's the better choice. But soups, sauces and drinks are hard to reheat in the basket, and defrosting takes longer. If you often reheat soup, stew or meal prep, you'll usually keep the microwave.
Usually the air fryer – but far less than the oven. In the test by the UK consumer organisation Which?, the microwave cooked a jacket potato in 8 minutes and used only just over half as much electricity as the air fryer; the oven used more than seven times as much as the microwave. The more you cook at once, the smaller the microwave's lead.
It depends on the food: liquid and saucy food in the microwave, crispy food such as pizza, chips or roast veg in the air fryer at around 160 to 180 °C. Reheat rice in the microwave, covered and with a splash of water – in the air fryer it dries out. Either way, the food has to get properly hot all the way through.
Yes, if you often make crispy food for one or two people – chips, roast veg, fish or chicken – and don't want to heat up the oven for it. For small amounts it's ready faster and uses less electricity than the oven. If you mostly reheat soup, stew and meal prep, a microwave serves you better; if you cook for a crowd, the oven does.
Mostly because of acrylamide: when potatoes, chips or bread are browned heavily, it forms in the air fryer just as in the oven. Germany's Federal Institute for Risk Assessment (BfR) advises: golden, not burnt, and ideally no hotter than 180 °C. Less fat also doesn't turn frozen chips and breaded food into fresh food. And the appliance gets hot: keep the clearances given in the manual and only put baking paper in the basket with food on top.
The microwave heats the water in the food directly, so food gets hot quickly but not crispy. The air fryer is a small fan oven: hot air browns the surface, which takes a little longer and makes food crispy.
Neither, across the board. The microwave often retains water-soluble vitamins well because it cooks quickly with little water. Compared with a deep fryer, the air fryer saves a lot of fat, but heavily browned potatoes produce acrylamide.
Set it about 20 °C lower and allow a good half to three-quarters of the oven time, depending on the food. Never cook potatoes, chips or baked goods above 180 °C. Check from halfway through.
A combination microwave with hot air saves space and is worth it if your kitchen is small and you use both regularly. For the hot-air mode you need heatproof dishes, as in the oven – no plastic. The instruction manual tells you what's allowed in combination mode.
No. According to the German Federal Office for Radiation Protection, the changes in nutritional value are the same as with conventional heating. Vitamin C is often even better retained than when boiling in lots of water. Pay attention to the container and to heating evenly.
Only containers with the microwave symbol – better not at all: heating releases far more micro- and nanoplastics than storage does. Glass or ceramic is the easy alternative.
At least 70 °C all the way through, especially meat, poultry and rice. Stir halfway and leave to stand briefly.
On fat, yes. But acrylamide still forms when potatoes and other starchy foods are browned heavily. Stay at or below 180 °C and cook until golden rather than dark brown.
Not breast milk, according to the CDC – use a bowl of warm water. Stir baby food from the microwave thoroughly and check the temperature.
This article does not replace advice from a doctor or dietitian.