The indoor grill has finally graduated from a novelty item to a legitimate culinary workstation. My recent “stress test” involving the Ninja DG551 Foodi Smart XL and the Ninja IG651 Foodi Smart XL Pro revealed a fascinating evolution in how Ninja manages heat.
While both units are designed to bring 500°F char-grill marks into your kitchen without the smoke, they are fundamentally different machines. One is a Convection Specialist designed to wrap your food in a vortex of heat, while the other is a Direct-Heat Powerhouse that functions more like a professional flat-top. Here is my first-person audit of which “Foodi” deserves your counter space.
The Key Difference: Ninja DG551 vs. IG651 Foodi Smart Grill
The primary distinction between these two models lies in their Thermal Delivery System.
- The Ninja DG551 (Atmospheric Heat): This unit is essentially a “box” oven with an incredibly powerful fan. It uses 500°F cyclonic air to heat the cooking chamber. The grill grate gets hot because the air is hot. It’s perfect for “surround-searing” thick meats and air-frying sides.
- The Ninja IG651 (Conductive Heat): This Pro model features a direct-contact heating element built into the grate itself. Because the grate is independently powered, it doesn’t rely on air to reach searing temperatures. This allows for the “Hood Up” mode, enabling you to sear and flip just like you would on an outdoor gas grill or a commercial griddle.
Technical Comparison Table: Ninja DG551 vs. IG651 Foodi Smart Grill
| Feature | Ninja DG551 (Smart XL) | Ninja IG651 (Pro Griddle/Grill) |
| Mechanical Style | Vertical Air-Box | Horizontal Griddle-Station |
| Primary Advantage | Deep-Cavity Roasting | Edge-to-Edge Direct Searing |
| The “Secret Weapon” | 2nd Gen Smoke Control | 12″ BBQ Flat Top Griddle |
| Doneness Logic | Smart Thermometer (Included) | Smart Thermometer (Included) |
| Height | 16 inches (Tall) | 7 inches (Slim) |
| Wattage | 1760 Watts | 1760 Watts |
| Cooking Modes | 6 (Grill focus) | 7 (Griddle/Flat-top focus) |
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Detailed Comparative Review: The Performance Audit
Design: Footprint and Kitchen Ergonomics
The DG551 is the “classic” Foodi silhouette. It is tall and compact. If your kitchen has plenty of open counter space but you’re tight on width, the DG551 is a master of spatial efficiency. I found that the vertical design made it excellent for air frying large batches of wings, as the air can circulate freely around the 4-qt basket.
The IG651, however, is a low-profile wide-body. At just 7 inches tall, it fits under the lowest cabinets I’ve encountered. But beware: it is wide. You’ll need a dedicated 18-inch stretch of countertop. The design is clearly influenced by professional “plancha” grills. When you lift the lid, the cooking surface feels more accessible; you aren’t reaching down into a “pot,” you’re working on a surface.
Ease of Use: The “Set and Forget” Factor
Both models utilize the Foodi Smart Thermometer. I tested this by cooking two thick-cut pork chops. In both units, the process is seamless: plug in the probe, tell the machine you’re cooking pork, and select “Medium.”
The DG551 felt more like an “oven” experience. I closed the lid and waited for the beep. Because it’s a closed-box system, it holds moisture incredibly well. The IG651 felt more like “active cooking.” I chose to leave the hood up for the first half of the cook to watch the sear, then closed it to finish. The IG651 gives you more control over the process, whereas the DG551 is better at automating the result.
Functions: The Versatility Gap
This is where the IG651 Pro pulls ahead for me. It includes a 12-inch BBQ Griddle.
I spent a Saturday morning using the IG651 for a full breakfast: eggs, bacon, and pancakes all sharing the flat-top. The temperature control across the griddle is remarkably even – no “cold spots” in the corners.
The DG551 is a 6-in-1 tool that excels at Air Crisping. Because the unit is taller, the distance between the fan and the food creates a more aggressive air vortex. If you are an “Air Fryer First” cook, the DG551’s roasting and baking functions feel more robust. But if you want to make smash burgers or seared scallops, the DG551’s grate-only system simply can’t compete with the IG651’s flat-top griddle.
Maintenance: Fighting the Grease
Grease management is the “hidden cost” of indoor grilling.
- DG551: The deep cooking pot acts as a giant grease trap. It’s very effective at keeping splatters contained. The removable splatter shield is a bit of a chore to clean by hand, but it is dishwasher safe.
- IG651: The flat griddle and grate are actually easier to scrub because they are flat surfaces without deep walls. The “Cool-Air Zone” in the IG651 also did a surprising job at keeping the smoke levels near zero, even when I was searing high-fat ribeyes at 500°F.
Ninja DG551 (The Reliable All-Rounder) Smart Grill
Pros:
- Space-Saving Width: Fits in tight kitchen corners.
- Roasting Depth: Large enough for a small roast or a thick loaf of bread.
- Speed: The cyclonic air heats up and cooks frozen foods incredibly fast.
- Value: Offers almost all the “Smart” features at a lower price than the Pro.
Cons:
- No Griddle: You can’t cook eggs, pancakes, or small stir-fry veggies easily.
- Cabinet Clearance: Needs significant room to open the lid vertically.
Ninja IG651 (The Professional Griddler) Smart Grill
Pros:
- Dual-Heat System: Powered grate for better searing + cyclonic air for crisping.
- Hood-Up Mode: The closest thing to an outdoor BBQ experience indoors.
- Griddle Included: Expands your menu to breakfast and diner-style favorites.
- Slim Profile: Easily clears upper cabinets.
Cons:
- Countertop Hog: Very wide footprint.
- Weight: It’s a heavy unit that you won’t want to move in and out of a pantry.
- Price: A premium price tag for the “Pro” features.
The Verdict: Match Your Cooking Identity
I recommend the Ninja DG551 if:
Your kitchen is a “Multitasking Hub.” If you want one machine to replace your air fryer and give you great grilled chicken and steaks on the side, the DG551 is the logical choice. It’s a high-performance convection machine that is built for speed and simplicity.
I recommend the Ninja IG651 if:
You are a “Searing Specialist.” If you love the art of the crust – whether it’s on a smash burger, a piece of salmon, or a pancake – the independently powered grate and griddle combo is a game-changer. It is a more versatile, professional-feeling tool for those who want to do more than just “air fry.”
My Take: The IG651 Pro is the winner in my house. The addition of the griddle effectively turned this from a “dinner machine” into an “all-day machine.” Being able to cook eggs in the morning and steaks at night on the same unit makes the extra width and cost worth the investment.
Frequently Asked Questions
Can I bake a cake in these?
Yes! Both have a “Bake” function. However, the DG551 is better for this because its deep-pot design mimics a traditional oven cavity more closely than the shallow IG651.
How loud are the fans?
They are comparable to a standard air fryer. On the “Grill” setting, you’ll hear a consistent whirring sound. The IG651 can be quieter if you are using the “Hood Up” mode, as the cyclonic fan doesn’t need to engage as aggressively.
Is the thermometer really “Smart”?
It is. It doesn’t just measure temperature; it tracks the rate of temperature rise to predict exactly when the meat should be pulled for carry-over cooking. It has never failed to give me a perfect medium-rare steak.
Do I need to use oil?
For the best results and the least amount of smoke, I recommend a very light coating of a high-smoke-point oil (like avocado oil) on the food itself, rather than the grate.
Are the plates interchangeable?
On the IG651, you can swap between the grill grate and the flat-top griddle. On the DG551, the grill grate is the primary surface, and you use the crisper basket on top of it for air frying.
