Ninja Double Stack Air Fryer review: a five-star gadget for small kitchens

RRP: £270 Buy now from Amazon | Buy now from Argos | Buy now from Currys

Our verdict

When it comes to the best air fryers, dual-drawer designs are usually the top pick for families due to their large capacity and ability to cook multiple dishes at once. However, they can be bulky, which isn't ideal if you're already struggling for kitchen space. Luckily, air fryer pioneers Ninja have come up with a solution: the oh-so-sleek Ninja Double Stack XL.

Instead of side-by-side drawers, this Ninja air fryer stacks its baskets vertically, making it 30% slimmer than the brand's leading AF400UK model. There's no compromise on capacity either; it still holds an impressive 9.5 litres across its two baskets, which is enough to cook around eight portions.

I'm a big fan of the Double Stack. In fact, I've become that friend who won't shut up about how much they love their air fryer. It looks sleek, is super easy to use, and the results are fantastic—in particular it cooked chicken and salmon beautifully, perfectly crisping up the skin without drying out the fillets.

The downsides? There's no getting around the hefty price tag. Ninja is a premium brand, and this is one of their more expensive models. Some reviewers also reported that it cooks food unevenly. It wasn’t an issue I encountered during testing, but I did check on the food about halfway through and gave it a shake or flip when needed.

Overall though, I really rate this dual air fryer. If you have the space, I'd go for Mumsnetters' favourite Ninja AF400UK air fryer. However, if, like me, you're limited on counter space, the Double Stack is a fantastic choice for families.

Cooking in the Ninja Double Stack XL Air Fryer: how easy is it to use?

With this being a relatively new Ninja offering, I was slightly apprehensive that it would be complex to get to grips with. Luckily, I was quickly proven wrong—in fact, it was surprisingly easy to use.

To operate the intuitive control panel, first you need to press the 'on' button. Then, if you're cooking just one portion, select '1' or '2' to choose your basket, use the dial to switch between the six presets—air fry, max crisp, roast, reheat, bake, or dehydrate—before pressing the temperature and timing buttons and adjusting the dial to get your desired settings. Honestly, once you've read the instructions and used it once or twice, it's an absolute doddle to operate.

If you're cooking in both baskets simultaneously, it's a very similar process, but you just need to press the 'Double Stack Pro' button before following the steps outlined above for one basket. Then, for the second basket, you can either press 'match', which applies the same settings to both baskets, or you can manually input different settings,. So, even if you're roasting at 180°C in one basket and air frying at 200°C in the other, you can cook both portions at the same time.

What's more, if your dishes have different cooking times, you can press the 'sync' button, so the two baskets finish cooking at the same time. I found this setting very useful, especially when preparing meat in one drawer and veg in another.

As with most Ninja air fryers, it doesn't have any settings specifically tailored to different food types (e.g chips, frozen food, chicken, vegetables), like you often get with models from other brands. When I was an air fryer novice, I found these settings really useful to have as they took the guesswork out of choosing temperatures/timings. However, it's not a huge issue, as the Ninja comes with a handy recipe book and a removable sticker with timings for popular dishes. Plus, I liked how clean the interface looks without a load of extra buttons.

Related: The best slow cookers for winter feasts

Ninja Double Stack Air Fryer SL400UK performance: how were the results?

I was thrilled with the performance of the Ninja Double Stack. During testing, I cooked a variety of meals in it, including chicken, salmon, a range of vegetables, garlic bread, frozen food, jacket potatoes, and much more.

As with any air fryer, there can be a bit of trial and error in getting the right timings, but overall, I found it cooked food fantastically—and at a far quicker speed than my fan oven!

Meat and fish came out perfectly without becoming dry, while cooking jacket potatoes in the air fryer resulted in delicious, crispy skin with soft, fluffy insides. Cheese on toast was also a highlight, and preparing it in the air fryer was far less faff than grilling it in my oven.

However, it should be noted that multiple reviewers found it didn't cook as evenly as Ninja's original AF400UK. I didn't have an issue with uneven cooking during my six weeks of testing, but this is something to bear in mind if you're choosing between the two different models. As a general rule, I tended to check on the food halfway through cooking and gave the basket a shake or the food a flip if needed, which may have helped with this issue. With that in mind, a 'shake' alert would be a good addition to this air fryer.

Related: The best microwave for a family home

Ninja Double Stack Air Fryer: design and style

The Ninja Double Stack Air Fryer gets top marks for style in my book. This sleek, white design is exclusive to Currys, and I think it would look great in many kitchens—particularly if you have a modern aesthetic at home. It's also available in grey and black/chrome designs too.

The biggest highlight of this air fryer's design, however, is the stacked layout. Rather than a traditional dual air fryer with side-by-side baskets, the baskets stack vertically, making it a great slim option compared to other two-drawer models. It certainly fit into my kitchen easily, though it is still quite bulky in depth. When using it, I did need to pull the fryer out on my countertop to ensure it had enough space around it. This was only a minor issue, though.

Related: The best air fryer for a family of four

Is the Ninja Double Stack Air Fryer easy to clean?

I was impressed by how easy the Ninja Double Stack Air Fryer was to clean. The baskets, crisper plates, and racks can be washed either in the dishwasher or by hand. I used both cleaning methods during testing and had no issues in this area, though Ninja does recommend cleaning by hand where possible for longevity.

Related: Best small air fryers

Price: is the Ninja Double Stack Air Fryer SL400UK worth it?

The biggest disadvantage of the Ninja Double Stack Air Fryer is its steep cost. With an RRP of £270, it's one of Ninja's most expensive air fryers. However, I used the Ninja daily during testing (and will likely continue to use it daily afterwards too!), so I think it's well worth it for a gadget that won't just be left to gather dust. Ninja also claims that it cooks food up to 55% quicker than a conventional oven, so it may also help you save on energy bills in the long run...

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How we tested the Ninja Double Stack Air Fryer SL400UK

I put the Ninja Double Stack Air Fryer SL400UK through its paces in my north London kitchen, whipping up a variety of treats with it including fish, chicken, veg, potatoes, plus much more. I tested it thoroughly over a period of six weeks, rating the air fryer on its set up, ease of use, ease of cleaning, design, value for money, and those all-important results.

• Tested in a four-person household over a six-week period

• Used daily during testing

• Cross-compared with other air fryers I've tested

About the author

Natasha Gregson is a Senior Content Editor at Mumsnet, with an expertise in home and kitchen product reviews and round-ups. With numerous years of editorial experience under her belt, her work has also been featured in prestigious national publications like The i Paper and Stylist Magazine, and she's written on a wide range of topics.

A keen foodie, Natasha oversees all kitchen content on Mumsnet, and has been on a mission to find the top gadgets, reviewing everything from toasters to air fryers, slow cookers to kettles.

When she’s not busy seeking out the best buys and advice for Mumsnetters, you can find her searching for the next best restaurant, watching live music, curling up with a good book, cross-stitching, or enjoying a good hike or run.

About Mumsnet Reviews

All Mumsnet product reviews are written by real people after extensive research and testing. We work hard to provide honest and independent advice you can trust. Sometimes, we earn revenue through affiliate (click-to-buy) links in our articles. However, we never allow this to influence our coverage.

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