I wanted to see if this old, affordable Shark vacuum could hold its own against the fanciest new models – I was amazed by the results

Shark Stratos IZ400: two-minute review

It might be looking a little long in the tooth now, but there's a reason the Stratos IZ400 is still part of Shark's vacuum cleaning lineup. This model packs a punch for cleaning power, and comes with a handful of special additions that help elevate it above the competition.

Standout features include dirt-based automatic suction adjustment and a forward-bending wand that makes it easy to clean under furniture, not to mention enabling the entire unit to fold in half for freestanding storage. But maybe my most favorite thing about this vacuum is that you can actually reach the on-off and mode buttons with your holding hand – something that's ridiculously rare on modern vacuums.

While the Stratos IZ400 isn't quite as efficient as the newer and pricier Shark PowerDetect, it still performed impressively well in my cleaning tests, proving equally capable on vinyl flooring, plus mid-pile and deep-pile carpet. Score-wise, it's up there with the best cordless vacuums on the market right now.

It won't be the best vacuum for everyone, however. The main downside is that it's rather heavy and bulky, and the PowerDetect pips it to the post when it comes to both special features and outright cleaning power. However, because it's older, this vacuum attracts plenty of discounts, with which it can represent incredible value for money.

Read on for my full Shark Stratos 1Z400 cordless vacuum review.

Shark Stratos IZ400 cordless review: price & availability

• List price: £429.99 / AU$799.99 (discounts common)
• Available: UK and Australia

The Stratos IZ400 has been out for a few years now, launching in 2022. Shark has released several newer models to its lineup since, including the Shark Detect Pro and PowerDetect Cordless.

In the UK, the list price for the Stratos Cordless IZ400 is £429.99, but it isn't difficult to find it at far less than this – at time of writing, it was available for £249.99 from Shark direct. This model is also available in Australia, where it costs AU$799.99 (reduced to AU$599.99 at time of writing).

At full price it's no doubt a premium model, but those discounts take it into mid-range territory. For what you're getting, it's excellent value for money.

• Value for money score: 4 out of 5

Shark Stratos IZ400 cordless specs

Shark Stratos IZ400 cordless review: design

• Heavy and bulky for a stick vacuum
• Controls are simple and effective
• Auto-suction adjustment and a forward-bending wand

Features include auto-suction adjustment based on how dusty the floor is, and enhanced anti-hair wrap design on the floorhead, an anti-odor capsule for keeping everything smelling fresh, and a wand that can be released to bend forwards to make it easier to clean under furniture. That last feature is also handy for storage, since it means you can fold the vacuum in half and it will stand on its own.

Like almost all cordless stick vacuums, the wand can be removed and the unit can be used as a handheld.

The main floorhead is Shark's older-style unit, featuring two separate rollers: a soft one for hard flooring, and another with rubbery fins for carpet. The front-mounted headlamps here are pretty dim, and won't illuminate dirt as effectively as those that feature on Dyson's laser floorheads. The Shark also lacks the "suction in reverse" feature included on the PowerDetect vacuums – this would prevent chunky debris from pooling up when the vacuum is pulled back over it.

Not too, that the IZ400 is one of the heaviest cordless stick vacuums I've used, weighing in at nearly 4kg with the wand and main floorhead attached. In handheld mode, however, it's fairly light – much of the weight is in the wand and floorhead, both of which are rather chunky.

Although the size and weight make it a little unwieldy, the IZ400 still feels decently easy to maneuver. Shark has added shaping and padding to the handle, which means it's easy to get a solid grip, yet it remains comfortable to use.

There are three modes to choose from: Eco (low suction), Boost (maximum suction), and Clean Sense IQ. That last one is the auto mode, where the machine will automatically adjust suction based on the level of dirt detected.

There are two control buttons: one switches the machine on and off, and the other lets you toggle modes. I was thrilled to discover that these are within easy reach of the handle – something that is bewilderingly rare on modern vacuums. It means you don't have to keep a spare hand free when cleaning, which is great.

Information is delivered via a screen above the handle. This is refreshingly uncomplicated – it tells you which mode you're in and how much battery remains, as a percentage.

Emptying the vacuum is simple, although you will need to remove the floorhead to activate the open-bin switch. Unlike on newer Shark vacuums, there's no compatible auto-empty dock.

The model I tested came with two attachments: a Crevice tool and a Multi-Surface tool, which is a wider brush tool for upholstery. Note, the one I tested here didn't have a motorized roller, as some upholstery tools do.

• Design score: 4 out of 5

Shark Stratos IZ400 cordless review: performance

• Strong cleaning on hard floor and carpet
• Auto-suction adjustment works well and saves effort
• Not quite as efficient as the Shark PowerDetect

During general use, I was impressed with the cleaning on offer here. I could hear the suction ramping up and down as I encountered patches of dust – and, despite the weight the vacuum, it felt relatively easy to maneuver and comfortable to use.

The forward-bending wand is great for cleaning under furniture. I was concerned the vacuum would be wobbly in this mode, but I needn't have worried – it felt sturdy and was easy to direct.

One thing I noticed is that the vacuum seemed to take a second to switch on each time. That's true of all Shark cordless vacuums I've tested, and although it isn't a deal-breaker, it is a bit irritating.

To gain a more objective view of the Stratos IZ400's cleaning powers, I ran a series of standard tests using fine debris (loose, dry tea) and chunky debris (a dry rice and lentil mix) on vinyl flooring, mid-pile carpet and deep-pile carpet.

Carpet

The Stratos IZ400 did a very good job on carpet, pulling the vast majority of tea from both mid-pile and deep-pile carpet in a single swipe. However, there was still a light sprinkling remaining – this model isn't quite as powerful as the Shark PowerDetect, although it is up there with other premium vacuums I've tested.

Chunky particle pickup was excellent, with very little debris pinged around the room. It should also be noted that the Stratos was easy to push in Auto mode, even on thick carpet. Some vacuums are ultra-powerful but are too sucky to actually push; I think Shark strikes a good balance here.

Hard floor

On hard floor, the Stratos cordless cleared the tea easily in a single forward pass in Auto mode. However, it caused the tea to pool up behind the floorhead when approached in reverse. This issue is widespread among such cleaners, but Shark has managed to fix it in its PowerDetect range, which has a newer floorhead design than the one found here.

Handheld mode and accessories

I also tested the Stratos in handheld mode, using the Multi-Surface tool to remove dry tea from an upholstered chair, in Auto mode. It did a decent job, although I found it worked better when the bristle part of the tool was removed. Some Stratos bundles come with a Motorized Mini tool – that's worth prioritizing if you have pet hair to deal with, for example.

Although this vacuum is actually relatively light in this mode, it's still a little unwieldy. The body of the motor section is quite long, and I found myself using two hands to keep things stable as I cleaned.

Battery

In Eco mode, Shark says this vacuum will last up to a full hour per charge. I timed it at 10 minutes in Boost, which is good. In Auto mode, runtimes will vary depending on the kind of cleaning you're doing.

The battery is removable and swappable. In fact, some bundles come with a spare, effectively doubling your cleaning time. One minor complaint I have is that it's really tricky to see how full the battery is during charging – there's a blinking battery icon on the side that switches off when the battery is fully charged, but it isn't displayed as a percentage, nor is there any kind of level indicator. The percentage on the screen also jumps down in 10% increments, rather than being precise.

• Performance score: 4 out of 5

Shark Stratos IZ400 cordless: scorecard

How I tested the Shark Stratos IZ400 cordless

I ran a series of trials in TechRadar's vacuum testing lab. These included seeing how well the vacuum could clear large (dry rice and lentils) and fine (dry, loose tea) particles from vinyl floor, mid-pile carpet and deep-pile carpet. I also assessed its general usability, flagging any pain points I encountered and shouting out any unexpected benefits. I compared my findings to other vacuums I've tested, and weighted all that up against the price, to gauge if this vacuum is a good buy or not.

Read more about how we test vacuum cleaners

• First reviewed January 2025