
As somebody who's spent a great deal of time testing vacuums, I can confirm that the cordless Dysons are among the best in the world. I own both the Dyson V15 Detect and Dyson V12 Detect Slim, as these are my favorite models I've ever tested.
But with the best Dyson vacuums consisting of so many models and variations, all with their own price points, it's not always easy knowing which one to choose.
So, here's a deep dive into the V15 Detect vs V12 Detect Slim, to find out which one is best suited to your home and worthy of your money.
Dyson V15 Detect vs Dyson V12 Detect Slim
Dustbin capacity: 0.2 gal
Suction power: 230 air watts
Weight: 6.79 lbs
Battery life: Up to 60 minutes
Read my full Dyson V15 Detect review here.
Dustbin capacity: 0.09 gal
Suction power: 150 air watts
Weight: 5.22 lbs
Battery life: Up to 60 minutes
Read my full Dyson V12 Detect Slim review here.
What's the difference?
Looking at the features and functionality of these two vacuums, two of the best cordless vacuums we've tested, they're almost identical. They look the same, are emptied the same, and have the same runtime and charge time. Both are Dyson laser vacuums that reveal invisible dust. Both have floor sensors to optimize suction based on how dirty your floors are or whether you're vacuuming carpet or not.
Both vacuums top the list of our best vacuums for pet hair guide. They also both have the same two floorheads, the Fluffy Optic and the Motorbar, which are incredible at cleaning hard floors and carpets, respectively. The Fluffy Optic has the signature laser, while the Motorbar has anti-tangle veins that have never once wrapped with hair.
Where they differ is in their size, suction power and price. The V12 Detect Slim is lighter at 5.22 lbs (compared to the V15's 6.79 lbs) and slimmer. Aside from making it the best lightweight vacuum we've tested, it's also more maneuverable, but comes with the sacrifice of a smaller dustbin.
The V15's dustbin is 0.2gal while the V12's is 0.09gal. That's one of the smallest dustbins you'll find in a cordless stick, and it means that you'll be emptying it a few times if you're ever vacuuming the whole house. But that's the case for most cordless sticks anyway...
The V15 is powered using a trigger, as opposed to the V12's on/off power button. This can be seen as an advantage or disadvantage, depending on how you vacuum. The trigger helps achieve quick bursts, vacuuming messes in different spots without keeping it running (and using up the battery) in between.
But for anybody with limited mobility – it's important to note that the trigger can become tiresome after long sessions. This is where the V12 comes in handy, and it wouldn't hurt to also consider one of the best robot vacuums to help with the endless day-to-day cleaning.
Which performs better?
The Dyson V15 Detect is the better vacuum cleaner. Although they function similarly, the V15 boasts higher suction power – 230 air watts to be exact, compared to the V12's 150.
As I explain in my vacuum jargon buster, air watts is the most accurate representation of a vacuum's suction. Wattage only represents the amount of power used, but air watts reflects the actual flow of air at a vacuum's intake nozzle. As a reference point, the best upright vacuums offer around 200-300 air watts, so the V15 Detect is as powerful as those corded, hefty powerhouses.
In real terms – the V15 cleans pretty much flawlessly (as shown above). You can certainly notice this when using them as a vacuum for carpet, as the V15 suctions itself to the soft flooring – again, just like an upright vacuum would. I've used it for months and it rarely fails to pick up mess – whether fine dust or long hair – in a single pass.
But both vacuums are among the most powerful cordless vacuums on the market. I used the V12 for around half a year before using the V15 and never felt like it was inadequate. It was only when seeing the V15's power first-hand that I appreciated that it is in fact a step up.

Over time, I have noticed that the V12 will occasionally leave some dirt behind, particularly if it's a stuck onto the floor in some way. But the V15 is more capable at pulling up stubborn dirt, whether caked onto hardwood floors or trapped in carpet fibers.
Which should you buy?
It all comes down to how much you're willing to spend, and how powerful you need your vacuum to be.
If your home is busier, perhaps with kids or pets, the V15 Detect is the better choice. Its larger dustbin avoids you having to empty it multiple times in a cleaning session, and its extra cleaning power is a must for all of the many, many messes that a busy household creates. Also, if your home is heavily carpeted, the V15 is the clear winner.
But if you don't need such robust suction, and you live in a home that's a little less messy like an apartment with predominantly hard floors, the V12 Detect Slim is more than enough. And you'll enjoy that it's lighter, easier to use, and $100 cheaper.
Buy the Dyson V15 Detect for $599.99 or the Dyson V12 Detect Slim for $499.99 direct from Dyson.
Our tried-and-tested picks of the best Dyson alternatives also offer up more affordable options for cleaning excellence.