Ninja vs Tower air fryer: Ninja DZ400UK or Tower Vortx Elite T17138?

Choose the Ninja DZ400UK if you mostly cook chips, nuggets, wings and other frozen food, want the hottest setting (240°C on Max Crisp) and the most power (2,470 W), and want to put the drawers and crisper plates straight in the dishwasher.

Choose the Tower T17138 if you cook big batches at normal roasting and baking temperatures, want a little more basket space (10.4 litres), a reminder to shake and the lowest maximum draw (1,700 W), and will register it for the full three years of cover.

Both cook two foods at once, both have a Sync mode that finishes them together, and both pause when you pull a drawer out. Neither maker lists a viewing window on these two models.

From Ninja we picked the MAX 6-in-1 Dual Zone 9.5L, the updated version of its two-drawer Dual Zone design, sold as the DZ400UK in Gun Metal Grey and the DZ400UKBK in Onyx Black. From Tower we picked the Vortx Elite 10.4L Duo Basket (T17138), a two-basket model in the same size class: on sale in Tower’s own shop on 1 November 2026, sold on Amazon and reviewed by Which? (first reviewed November 2024).

If you have the older Tower Vortx 9L Dual Basket (T17088) in mind, we cover it under “Other Ninja and Tower options” below: Amazon and other retailers still sell it, but on 1 November 2026 Tower’s own shop showed it as out of stock.

This is the biggest difference between the two. The Ninja draws 2,470 W and its Max Crisp function runs at a fixed 240°C, a setting made for frozen chips and nuggets. The Tower draws 1,700 W and tops out at 200°C on every preset; its manual sets Fries and Chicken to 200°C by default.

Spread over the drawer space, that is about 260 W per litre for the Ninja and about 163 W per litre for the Tower. It is a rough guide, not a test result, but more power per litre usually means faster recovery after you load cold food and crisper edges on frozen food. Tower’s manual also tells you to add 3 minutes if the fryer is cold; Ninja’s booklet says its fryer doesn’t need preheating.

Where the Tower’s lower ceiling matters least: roasting vegetables, drumsticks and fish, and baking, for which its manual suggests 150°C.

On paper the Tower is bigger: two 5.2-litre baskets against the Ninja’s two 4.75-litre drawers, about 9% more space. The makers’ own serving claims run the other way: Ninja says the DZ400UK feeds up to 8 people and takes a 2 kg chicken in each drawer; Tower says the T17138 suits families of up to 6.

Which? warns in its guide to dual air fryers (1 October 2026) that claimed litres don’t always match how much food really fits. Its review of the T17138 gives a maximum cooking capacity of 2.4 kg. It hasn’t reviewed the DZ400UK, but for the earlier Ninja AF400UK, which has the same two 4.75-litre drawers, it gives 2.2 kg: eight to ten portions of chips or six chicken thighs. On those figures the Tower holds slightly more, roughly one extra portion of chips.

• A household of 2 to 4: either is plenty; one drawer handles most weeknight meals.
• 5 or more, or batch cooking: both work; the Ninja’s heat helps with large loads of frozen food, the Tower’s bigger baskets with roast veg in a single layer.

SharkNinja’s UK spec table and the DZ400UK instruction booklet list the drawers and crisper plates as dishwasher safe, although Ninja recommends washing the drawers by hand to make them last longer. Tower’s T17138 manual is blunt: the cooking baskets are not dishwasher-proof, and you should wash them and the grill plates with hot soapy water and a non-abrasive sponge. Which?’s specification table for the T17138 says dishwasher safe; we go by the maker’s own manual.

Tower also asks you to clean the fryer after every use and warns that metal utensils and abrasive pads damage the non-stick coating. If you air-fry most days, that is a real chore to weigh against the longer guarantee.

Ofgem’s price cap for 1 October to 31 December 2026 sets an average electricity unit rate of 26.32p per kWh for Direct Debit customers on a standard variable tariff in England, Scotland and Wales (announced 26 August 2026). That rate already reflects the government’s removal of VAT from electricity bills from 1 October 2026 to 31 March 2027. The standing charge is paid whatever you cook, so we leave it out.

• Ninja DZ400UK, 2,470 W: at most 65.0p an hour, or 21.7p for a 20-minute cook.
• Tower T17138, 1,700 W: at most 44.7p an hour, or 14.9p for a 20-minute cook.

These are ceilings: both fryers cycle their heaters once they reach temperature, so real use costs less, and a less powerful fryer can need longer to cook the same food. Either way the gap is a few pence a meal. Ofgem announces the next cap on 25 November 2026, for 1 January to 31 March 2027, and we will update these figures then. On a fixed or time-of-use tariff, or in Northern Ireland, use the unit rate on your own bill.

Guarantee. Ninja’s DZ400UK booklet gives 1 year as standard, or 2 years if you register within 28 days; buying direct from Ninja registers it automatically. SharkNinja’s product page simply shows 2 years. Tower’s T17138 manual gives 12 months, extended to 3 years if you register online within 28 days of purchase, and says the warranty is void if you fit non-Tower spare parts.

Spare parts. SharkNinja’s UK site sells replacement left and right drawers for the DZ400 series. Tower’s manual lists a replacement grill plate (T1714401) and left and right baskets (T1714402 and T1714403), to order through its website or customer support line; on 1 November 2026 Tower’s online shop listed baskets for other models, such as the T17088 and T17136, but none for the T17138.

Recalls. The Office for Product Safety and Standards published a recall of six Tower air fryers on 8 April 2025 (updated 24 July 2025 and 9 March 2026) because they could overheat and catch fire: the T17023, T17061BLK, T17067, T17087, T17129L (sold by Lidl) and T17129 (sold by Argos), made between January 2022 and April 2023. Neither the T17138 nor the T17088 is on that list. A search of the GOV.UK product safety alerts on 1 November 2026 found no Ninja air fryer recall.

• Tower Vortx 9L Dual Basket (T17088): the Tower many people mean by “Ninja vs Tower”. Tower lists two 4.5-litre baskets, 2,600 W, 50 to 200°C and a 60-minute timer. On 1 November 2026 Tower’s own shop showed it as out of stock, while Amazon and other retailers still sold it; check which model you are getting before you buy.
• Tower Vortx Vizion 8 Litre Digital Dual Basket (T17151): two 4-litre baskets with viewing windows and internal lights, if you want to watch food cook without opening a drawer.
• Ninja 6-in-1 Dual Zone 7.6L (DZ300UK): the smaller two-drawer Ninja; SharkNinja says the DZ400UK cooks up to 25% more.
• Ninja Double Stack (SL300UK, 7.6 litres, or SL400UK, 9.5 litres): two drawers stacked one above the other, for narrow worktops.

We don’t test air fryers ourselves. We compared the specifications on SharkNinja’s and Tower’s UK websites and in both makers’ instruction manuals, read the published findings of Which?, the UK consumer association, and checked the GOV.UK product safety alerts and Ofgem’s price cap. Where a maker’s pages, its manual or Which? disagree, we say so. Specs and pages were read on 1 November 2026.