SHARK BU3521 Clean & Empty Cordless Stick Vacuum

Yes. The Shark BU3521 has strong suction on carpet and on hard floors, and it ramps up on dirty patches without a mode change. The multi-surface brushroll adjusts its speed to the floor, so one head covers both, which makes it practical for homes that switch between rugs and bare floors room to room.

Well. Setting the Shark BU3521 back on its dock empties the small stick bin into the base, so you rarely handle dirt at all. A Quiet Mode lets it dock and charge silently and leaves the emptying for later, which helps when someone's asleep or the dock sits near a living area.

Yes. The stick itself is light and easy to move, which makes a quick daily pass around the kitchen or hallway easy. The spec record gives 12.3 lb for the BU3521, and the handvac comes off the wand for stairs and upholstery, so you aren't lifting the whole thing on steps.

It depends on the house. Shark rates the BU3521 at up to 40 minutes in ECO mode, and for some a charge covers a full clean. One reported run lasted about 15 to 20 minutes before fading, not enough for a whole home, so larger houses may need a recharge mid-clean.

Stairs are on its listed surfaces along with carpet and hard floors. The handvac comes off the stick for above-floor jobs like steps and upholstery.

A HEPA filter with what Shark calls an Anti-Allergen Complete Seal. The stick's own bin holds 1.3 liters before it goes back to the dock.