# Ninja Double Stack XL SL400UK

**Category**: air-fryers | **Price**: ~$250–$270 | **Reviews referenced**: 1536
**Last updated**: 2026-04-17
## One-line verdict
Ideal for families needing large capacity in small kitchens, but trades off even cooking and speed for its ultra-compact stacked design compared to side-by-side dual-zone models.

## How it compares

- vs Ninja Double Stack XL SL401 ($250–$300): SL400UK wins on lower price, SL401 wins on broader US market availability and potentially updated feature set
- vs Ninja Foodi DualZone XL DZ401 ($180–$200): Double Stack wins on vertical footprint saving counter width, DZ401 wins on wider baskets for even cooking of flat foods like fries and chicken pieces
- vs Ninja DZ201 Foodi 8 Qt ($180–$220): Double Stack wins on total capacity in a smaller footprint, DZ201 wins on lower price and wider basket surface for even crisping
- vs Ninja Foodi DZ550 10 Qt ($200–$250): Double Stack wins on compact vertical design for small kitchens, DZ550 wins on 10 qt total capacity and Smart XL cooking intelligence

## AI-summarized review themes

### Frequently Praised
- Stacked design saves counter space while cooking enough food for four to eight people
- Sync feature cooks different foods at different temperatures, finishing simultaneously every time
- Dishwasher-safe drawers and racks make cleanup easier than a traditional oven

### Frequently Criticized
- Uneven cooking due to rear-mounted heat, requires frequent shaking and flipping
- Significantly longer cook times than side-by-side models, sometimes double for basic foods
- Perforated baskets allow drips and are difficult to clean thoroughly

## Best for
families of 4+ in small kitchens, cooking multiple dishes simultaneously, replacing oven for everyday meals

## Not for
buyers prioritizing fast even crisping without babysitting food, small households wanting quick single-basket cooking, minimal cleanup fuss

## Specifications
| Spec | Value |
| Cooking Capacity | 9.5L (2x 4.75L drawers) |
| Countertop Footprint | H38.5 x W28 x D47 cm |
| Cooking Functions | 6 (Air Fry, Max Crisp, Roast, Bake, Deheat, Reheat) |
| Wattage | 2470W |
| Dual-Zone Cooking | Yes, with independent controls and SYNC |
| Dishwasher Safe Parts | Drawers, racks, crisper plates |
| Weight | 10.3kg |

## Data sources
- Estimated ~1536 purchase reviews via Argos
- 1207 reviews via Currys
- Multiple verified purchase reviews via Amazon UK
- Review period: 2024-2026
- Sentiment confidence: high